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xanavisilvia
12-01-2003, 03:08 AM
Hi everyone,
I'm new here.
I just purchased a used 99 Cobra with 54k miles on the odo.
The car is bone stock and was wondering what kind of gas mileage are you guys getting?
I was just curious.
Thanks for your help.

tcrews
12-01-2003, 08:10 AM
You should expect around 25 mpg on average...maybe 24. I used to get 28 mpg on the highway in my 1997 Cobra when it was relatively stock (AC on too).

spittincobra01
12-02-2003, 04:55 PM
to be totally honest, I only monitored my gas milage once... on a trip from home (NH) to Georgia (Duluth/Raod Atlanta) and I think it was something like 27 MPG on the highway with moderate acceleration from gas stops and tolls. I haven't monitored it since. but then again, I didn't buy a cobra for fuel economy ;)

smashedheadcat
12-02-2003, 04:58 PM
I can get 330-360 miles out of a tank on the highway with my 97 blown vert. And, going roughly 75-80mph most of the way.

Stavesacre21
04-19-2004, 12:47 AM
Hey all! I'm new to the Mustang Cobra family, and just got my baby last friday. Rio Red 1997 Mustang Cobra convertible (#2595 of 3088). It's great to see a group of such tightly knit people!

Anyhow, on my first tank of gas, i bout freaked out. I was sittin on empty after only 220 miles! Granted that almost ALL of them were in town, starting and stopping, it still had me rather shocked. I really wasn't even hard on her either.....i mean, not much activity above 3K RPMS. It equalled out to 18.5 MPG, which may be about right by the EPA, but compared to your numbers of 25-28, WOW. Does highway miles really bump the averages up almost 7-9 MPG? Just a little curious what you all think of this! Should I be concerned about this? Anything I can do to better it?

Oh yea, and BTW, she's bone stock - not a single mod - 36K on her

Firme
04-19-2004, 01:52 AM
I get 16mpg city, but that is with a very very heavy right foot. I basically can never get in my car and drive anywhere without taking the rev's above 5krpm at least a few times.

I think my highway trips have been around 25mpg

I have actually heard of people with 4.10 gears getting better mileage out of their snakes.

Stavesacre21
04-19-2004, 06:28 AM
well i guess it's at least nice to hear that someone out there is experiencing mpg's in the teens, even if it is with a lead foot at times. I'll admit that since this was my first weekend with the cobra, i pushed her a few different times to see what she could do, so that might account for more then I orginally thought. Anyhow, this initially just had me baffled beyond all compared, but i guess it was my first tank of gas so i'll probably play it cool until i can get some more numbers off of hwy miles and all. :D

tcrews
04-19-2004, 08:26 AM
Yes, highway driving will definitely increase your mileage. Once the car is in motion it's easier to keep it in motion and maintaining a speed uses less gas than constantly starting from a stop or increasing your speed.

Also anytime you go above 3250rpm you are opening the secondary intake ports (the IMRCs) which increases your gas expenditure greatly. Stay under 3,000 rpm, keep the car moving at a steady speed and you can get 28 mpg easily (with the AC on).

In town don't expect much, stopping and starting over and over will kill your mileage.

nckissfan
04-19-2004, 02:07 PM
Hey all! I'm new to the Mustang Cobra family, and just got my baby last friday. Rio Red 1997 Mustang Cobra convertible (#2595 of 3088). It's great to see a group of such tightly knit people!

Anyhow, on my first tank of gas, i bout freaked out. I was sittin on empty after only 220 miles! Granted that almost ALL of them were in town, starting and stopping, it still had me rather shocked. I really wasn't even hard on her either.....i mean, not much activity above 3K RPMS. It equalled out to 18.5 MPG, which may be about right by the EPA, but compared to your numbers of 25-28, WOW. Does highway miles really bump the averages up almost 7-9 MPG? Just a little curious what you all think of this! Should I be concerned about this? Anything I can do to better it?

Oh yea, and BTW, she's bone stock - not a single mod - 36K on her


don't feel bad, I bought my 97 vert in Jan. The first few tanks I got 235-240 miles to the tank(almost empty). I put a K&N air filter on, and now I get 260 miles to a tank, unless I get in the gas a lot, which I do :D . I can't help it, these cars are so fun to drive fast!

redsnake99
04-19-2004, 04:05 PM
In my 99 blown Cobra convertible I get 300 miles out of a tank on the road, 6th gear. I get an average of 220 miles per tank for everyday driving. I get around 50 miles per tank on the open track.

:thumbsup:

nckissfan
04-19-2004, 04:27 PM
In my 99 blown Cobra convertible I get 300 miles out of a tank on the road, 6th gear. I get an average of 220 miles per tank for everyday driving. I get around 50 miles per tank on the open track.

:thumbsup:


run that mother hard on the race track!! :D I have not been on the highway for a whole tank of gas yet, so I will have to wait and see when that happens.

Bartman01
04-19-2004, 06:19 PM
I typically range mid 17s to low 20s with mixed driving. I probabaly avg around 19-20 around town. I am getting about 1-2 MPG better than I did with my old Maxima. I am running the stock gears. Going with taller gears would help improve mileage around town. With the stock gearing many city streets have you revving close to 2000 rpms - and the next gear would be a bit too low in the rpms.

Stavesacre21
04-19-2004, 10:39 PM
Thanx for all the input fellas! It's really awesome to see such a tightly bound group of devoted owners. I've only known of this owners group/forum for a little less then 3 days, and already I can see that it's different then any other forum i've ever posted at. I look forward to postin regularly, as well as getting to know more and more about my Cobra, which I've only had for 5 days! Thanx again for the help! :D

ausie
04-20-2004, 07:14 AM
On average I get close to 22 mpg. Most of my driving habits is 80% WOT the 20% of it is for the posted speed limit when driving through the watched areas (I don't like speeding tickets). I get better gas milage with the COBRA than with my Ford Explorer (11.2mpg average). I have yet to take the Cobra on a long trip to see what kind of milage I would get out of a full tank. When on the highway and driving normally, I can easliy get 100 miles on a 1/4 tank if not more (the temptation to push it is often too great :D and hard to resist :cool: ). I would probably get better gas milage if I used that last gear (would that be 5th gear?) Dang I forgot I had an overdirve gear. This car is too much fun to drive in 3rd or 4th down the highway especially when there is no traffic! Enough said. I usually keep it cool and I don't take too many risks when dirving, especially when I have passengers too.

spittincobra01
04-20-2004, 07:17 AM
funny you say that... My cobra is the most economical vehicle I own fuel wise :thumbsup:

Stavesacre21
04-20-2004, 03:48 PM
funny you say that... My cobra is the most economical vehicle I own fuel wise :thumbsup::eek: I listen in disbelief! What else ya got in your garage? Viper? Couple Ferrari's? Possiably a Lamborghini?! :rotf:

Guess that in the overall spectrum of SUV's, the Cobra is shockingly superior on gas milage (as well as HP :thumbsup: )

Bartman01
04-20-2004, 07:51 PM
:eek: I listen in disbelief! What else ya got in your garage? Viper? Couple Ferrari's? Possiably a Lamborghini?! :rotf:

Guess that in the overall spectrum of SUV's, the Cobra is shockingly superior on gas milage (as well as HP :thumbsup: )

The Cobra gets better milage then my Maxima did and our Pathfinder does. It beats the Pathfinder by 2-3 MPG easily in the city and on the highway it's not even close.

spittincobra01
04-21-2004, 11:17 AM
well now that Ive sold off a few vehicles what I have left is a 2001 4X4 F150 SuperCrew w/ 5.4, 2001 Explorer Sport, and the 2001 Cobra. in the city the exploere hangs with the snake for gas milage.... but on the highway nothing even comes close! :eek:

and I have a very heavy go pedal foot

Stavesacre21
04-21-2004, 09:14 PM
but on the highway nothing even comes close! :eek:
I'm starting to see how that is possiable, considering the fact that at 70MPH, she's sittin pretty at barely above 2K RPM'S. Matched with a steady foot (aka cruise control) I'll bet it's no competition!

Stavesacre21
04-25-2004, 11:27 PM
OK, my gas milage is really starting to get me preturbed...filled her up for the second time tonite. I've went about 111 miles on this run (not empty, but just to figure milage), and milage figured out to barely over 20 MPG. This may normally sound pleasing, but the fact that it was ALL highway driving with cruise on makes me a little :mad: . I guess it's just how I hear of the 25-28 MPG that many are getting, and it kinda gets me worked up. I know, i know......no one buys these kinda cars for gas milage anyhow, but still, it's just killin me as to why this might be. All of my accelerating was below 2500 RPM's, so I figured that racing would get me ALOT worse milage. Anyhow, not really whining to anyone in specific, just fillin everyone in as I mentioned that I would. Any tips for improving this number? Any maintence that could damper gas milage that bad? Just wonderin...:banghead:

ausie
04-26-2004, 07:08 AM
It all depends on how many miles and driving habits. If your stang is stock without major mods (supercharger, turbo, gears, etc) you should average 20 to 22 mpg. Most of my driving is off the highway and everytime I get on the highway it is very hard to do the speed limit unless there is considerable traffic. As vehicles age so does the fuel economy (but in the other direction). Fluids come to mind in that reduced friction aids in performance. One thing overlooked are the spark plugs. Regardless of what type of plug you are running (even platinum plugs) should be replaced at regular intervals. There are several inconsicuous factors that may reduce fuel milage one namely being increase in back pressure and the other carbon buildup. Carbon not only fowls plugs but it makes the engine run hotter as well as cause build up in the cats. There are several methods to remove deposits from a motor, one method (easy) is water mist into the throttle body to steam clean the engine and all other parts. If done with care it will work great, but it is not fool proof. I used to clean the intake on my escort with carb cleaner every oil change, but now I have started to do that with the cobra since I had severe carbon build up. It was so bad I had to use water injection to remove it. If you are concerned about popping a hole in a piston, you could opt for the other method of choice which is called "CARVAC" which can be done at a dealer. They do very much the same thing but have a special vaccum to clean out the Emissions components. The main cause in the fuel consumption is a dirty EGR valve where the recirculated gases begin to dwindle as the passaged begin to close from the deposits which in turn causes the computer to enrich the fuel to prevent pining. One of the hidden features of the EGR system is that it reduces pinging by adding "octane" to the fuel air mixture. "Octane" is just about anything that reduces the burn rate of fuel. If you suspect the fuel milage is under par, I would recomend either the "carvac" wich will cost a mere $180 or attempt to do it yourself with a $4.00 can of good intake cleaner and a few tools. The process will take several hours then followed by a complete oil change. I did alot of research on this since I had nasty pinging and carbon buildup. While at the ford dealer, I heard the service guy slip by saying "or you could just spray 4 cans of the Ford intake cleaner into the motor" which is what they would probably do in the first place and charge me the $180 to $200. The trick is to spray while the engine is running (more on that later).

Stavesacre21
05-03-2004, 09:25 PM
After talking to a few people who seem to know their cars inside and out, I'm starting to hear alot about O2 sensors goin bad. Does this sound like accurate? It sounds good to me, but if so, i'm just kinda surprised i hadn't heard it from any of my SVT buds yet.

BTW, does the Cobra have 2 or 4 sensors? Chances are likely it's 4, but i just wanted to make sure...cause i may end up havin to buy some.

ausie
05-04-2004, 05:17 AM
While wandering under the car on a roll back, I only noticed two O2 sensors, if there are more than two, I suspect they may be located somewhere above the pre-cats on the headers.

Oh yeah, another means for loosing gas milage or the appearance of loosing gas milage is change in wheels and tires. I recently put new wheels on the car for the summer, but the rears are 1/2 inch shorter in overall diameter. Since the odometer is digital and driven by a signal on the trans, it appears that I am not putting as many miles on the car since there is an error in the speed reading of
-4 percent. Hence the gas milage looks as if it is loosing ground a bit. Without correcting the error in the speedometer, the trip odometer will be based on that error as well.

Stavesacre21
05-04-2004, 08:47 PM
Well, i ran by advance auto today and asked them about the sensors. They looked them up, and sure enough, there are indeed 4. In all likelyhood though, most of the people there didn't seem to think that an O2 sensor would go bad at 37K.

Then it struck me. Yes yes, to my stupidity, i hadn't even thought of it. The car had only been drove 800 miles for the last 2 years, so I didn't know if the oil had been changed. Contacted the last owner....nope....hadn't been changed yet! SO, i changed it up today using Mobil 1 and a K&N filter.

Do you all think that 2 year old oil would decrease milage? The oil wasn't pitch black or anything, but still had been in the engine for about 2 years it seems. Looks like i'll be running this tank empty, and we'll see if this makes the difference or not! Kinda excited to see what develops :bounce:

If yall have the time, lemme know your thoughts on this!

P.S. - Thanx for all the help ausie...btw, i have factory rims and tire sizes as listed

ausie
05-05-2004, 06:06 AM
At 37k miles, that is another story..... At least the miles were low. By the way, O2 sensors can go at any time, even though they are supposed to last longer than one would expect. More than likely it is something else other than an O2 sensor. But then again, the mustang is not considered a fuel economy vhehicle. You could always go to autozone and have the codes read even though the the MIL or check engine light is not tripped. Sometimes a sensor goes bad or is out of range and causes a pending code to be suspended since the computer is able to compensate for the sensor fault. The next thoughts come to mind is how clean is the intake plenum? Mine was black coated with oil vapor and carbon deposites all the way to the pistons at 20k miles. Having dual over head cams and possibly insuficient baffles in the valve covers, oil tends to get sucked out of the motor and winds up in the intake along with the carbonized gasses from the EGR valve tends to make the intake and combustion chamber a bit dirty. I wound up replacing the fuel filter (which by the way should be replaced at intervals of 16k miles) I had carbon build up that just about any fuel would ping even with fuel additives. Fuel additives will not correct carbon deposits. They may help prevent it but will not remove carbon if the build up is thick enought. I eventually decided to inject water into the intake with the engine running, with a followup with intake cleaner which helped to clean out the combustion chamber. Carbon deposits is a normal thing that occurs with the amount of back pressure present, lack of scavaging from the cylinders, etc... a film of carbon on the spark plugs is enough to reduce effective spark. Usually the power produced it lower when the carbon deposits get on everything including the valves. Another thrick, check the MAF (mass air flow sensor) any oils or dirt that may be on it may cause the fuel mixture to be out of desired ratio. If it is dirty, clean it with electrical cleaner spray, but do it when the engine is cold and not running - ignition must be off since it is a hot wire sensor. Some cold air kits cause turbulance in the MAF which makes it work improperly. Just some thoughts nothing more. Just a reminder, those platinum plugs do not last 100,000 miles. I am sure you could drive a car that long, but the end results on the same plugs may not be desired. The original factory plugs in my cobra lasted about 16k miles (the time I started having carbon build up, major pinging, and spark plug fouling) (I had a cold air kit installed which I think was the catalyst in the carbon build up, only drove 2000 miles with it installed when the pinging and stalling issues became abundant). Some CAI's may be worth the money, but the one I installed was not.

Stavesacre21
05-06-2004, 12:28 AM
Wow, I feel like I just read a chapter of a greek book....lol.

So ausie, do you work on cars for a living? If not, how on earth did you learn so much about the Cobra engine? I can see you've only been a member for a month or so, but really seem to be active.

Nevertheless, thanx for all the info. If the old oil isn't my problem, i've got enough stuff to check out to keep me busy for...oh...say....eternity. LoL.

ausie
05-06-2004, 06:54 AM
I am an electrical engineer, and computer programmer. I have (at least I think) developed my knowledge base from forums like this, and tinkering around with my car. Research has helped me with many of the problems that I have faced with my car. Although not severe, but noticable. Once you cover the basics, the mysteries with the new electroncs and how they work becomes simplified. Funny though, I used to think fords were hard to work on, but the Cobra is the easiest to work on. So easy, I am even contemplating on changing my first clutch myself, I have covered that subject in length when I own an Escort but since that was front wheel drive it seemed too complicated. I am always learning about the car something new or something I thought I knew but did not. I guess my beginnings into the motor was trying to determine why I had carbon deposits to the point of causing pre-ignition ping. As it turned out, a simple change in the intake and a poorly operating EGR was the culprit along with the MAF getting a little dirt on it. Blame it on the internet:D . Not only is there information withing the mustang enthusiast sites, it exists elsewhere too. As for carbon deposits, at least I know that the 4.6L is not the only motor that has that issue. BMW's are best known for pinging on american fuels and the cuase was carbon deposits in the combustion chamber. How to get ride of it was another thing to search for. As for the cobra engine, I read alot of magazines on Fords. I guess you can call it a hobby. The need for more speed has lead me to understand what I can do and what I cannot do with the stock parts. As for adding a supercharger to a stock 01 motor, I could probably get by with a kenne bell pushing 6psi but yet the stock motor does not have forged pistons or connecting rods I would certainly hate to put a hole in a piston. Especially with close to 10:1 compression, adding a supercharger would require higher octane fuel than I could get at the pump. I am in here for much the same reason anybody else is here. Besides that, I in my opinion, the Cobra is a great car no matter what the model is or year, I think it deserves the recognition this and other forums place on it. Since it was my first high performace vehicle I ever owned I knew ahead of time that a different preventive maintanance would be needed. Owning a Cobra is like owning a fine tuned porsche or ferrari. Believe it or not, I compared the Cobra to other cars such as Audi, BMW, Mercedies, etc.... even though those cars cost more than the Cobra, there was no difference in quality of workmanship and materials. Not only was the Mustang more bang for the buck, it also held a large aftermarket support and the parts for repair does not cost an arm or a leg to obtain them. No car is perfect, but the cobra comes close. Dang, if I only waited another year I could have had an '03. Nah, I like my 01 just the same! If I loose a race to one that is fine with me, at least it is another mustang :thumbsup:

AF24
05-06-2004, 10:29 AM
I'm curious too....

I have factory gears in my 98 right now with o/r pipe mufflers and a CAI, but I just ordered 4.10's.

I plan on taking the car to myrtle beach mustang week this July, which is about 6 1/2 hours from here. Would that be stupid? What kind of gas mileage will I be looking at if I just drive it steady?

Stavesacre21
05-06-2004, 06:39 PM
What kind of gas mileage will I be looking at if I just drive it steady?Thus we come back to the ORIGNAL question. lol

If you read all the above, you'll see that gas milage varies VERY much so in the Cobra community. I've heard one say up to 28MPG on the highway, although I've hardly broke 21MPG on the highway myself. Aftermarket mods and upkeep of maintence on the vehicle are some of the primary deterministic factors controlling gas milage. However, the classic #1 factor is how hard you push her. Although unconfirmed, by the looks of this post thus far, it seems as though the verts seem to get very slightly less milage then the coupes. My guess would be that you could expect between 21-25MPG. Whatever the case, be sure to fill us in on how it's lookin! :thumbsup: If you're up for a 7 hour drive, more power to ya! Just more bonding time with your baby!

xanavisilvia
05-06-2004, 09:56 PM
When I had my 98GT, I installed 4.10s and was loving it. I could actually use my 5th gear on highway. And the best thing was that my gas mileage was not effected. I think it got little better after the gear swap. I was shifting more frequently, which I really enjoyed. It felt like I was really driving my car. So, AF24 do not hesitate to put 4.10s in your car.
DO NOT FEAR THE GEAR!!!!!!

ausie
05-07-2004, 05:14 AM
4.10 gears will not change much from the 3.27 stock. The only thing it will do is make it look like you are loosing gas milage due to the different speedometer readings. I still have stock gears but the ratio is different due to 1/2 inch difference in overall diameter of the tires. It appears that I have droped in fuel milage. Actually 4.10 gears will effectively lower the load on the motor since you are gaining leverage with a taller gear ratio. I barely use 5th gear anyway, even on the highway I usually stick to 3rd or 4th since I like having a positive feel in throttle response while driving. I even find myself driving in town only using 2nd gear. I could only imagine what my mileage would be if I dogged it most of the time. 35mph it hard to maintain, 25 is even harder. Sometimes I even think my car is too fast in neutral :D. You could use one of the calculators that can be found in "allfordmustangs" site. http://www.allfordmustangs.com/index.shtml
http://www.allfordmustangs.com/AFM_Tech/Calculators___Decoders/index.shtml
Some of the information located there can be interesting.

Stavesacre21
05-08-2004, 11:32 PM
I barely use 5th gear anyway, even on the highway I usually stick to 3rd or 4th since I like having a positive feel in throttle response while driving. I even find myself driving in town only using 2nd gear. I could only imagine what my mileage would be if I dogged it most of the time.
omg.....i couldn't even imagine what kinda gas milage you get if you sit in 3rd at highway speeds! :eek:

ausie
05-09-2004, 07:36 AM
When the average highway speed is 80mph, 3rd gear is great for passing! then pop it into 4th when you get above 110mph. I guess my driving habits should change a bit since the cost of fuel is increasing. Most of my highway driving is on the turnpike, and if linger in the passing lane too long you might get rear ended at 80mph. 65mph or 55mhp are the posted speed limits which I find relatively dangerous to maintain on the turnpike since you create a stationary object on the road for other dirvers. I have tried driving the posted speed limit on the turn pike and nearly got hit every time. It is much different on the other highways (closer to the speed limit if not lower at times) which tend to have more car or truck accidents on them. I am just surprised that on the Highway, at just about any speed the car gets great gas milage. Note: I do not maintain excess speed on any road since I do not care much for pine boxes and or speeding tickets. Lately, I have been ignoring the temptations to take the car to its limits. Also, in town driving, the car does not boast such great gas milage where speeds at 25-35 get sticky when choosing gears, mostly 2nd gear and some times 3rd to maintain less of a load on the motor. I get about 19mpg in town which is mainly due to the stop and go traffic pattern. Most of my driving in the Cobra is for fun since it is a recreational vehicle. It doubles as a daily driver during the late spring and summer months

Stavesacre21
05-30-2004, 01:19 AM
don't feel bad, I bought my 97 vert in Jan. The first few tanks I got 235-240 miles to the tank(almost empty). I put a K&N air filter on, and now I get 260 miles to a tank, unless I get in the gas a lot, which I do :D . I can't help it, these cars are so fun to drive fast!
He speaks words of wisdom! Changed out the K&N filter ONLY, and changed a highway trip from my last one (20 MPG) to a whopping 25 MPG!!! This is by far the most effiecient upgrade if yur lookin for a quick fuel fix (assuming you haven't changed your filter recently (within the last 30K miles)

Thanx for all the help buds......finally found my problem! :thumbsup:

Stavesacre21
07-03-2005, 09:34 AM
Just thought i'd fill everyone in on my astounding milage i got

On the way down to South Carolina, I got an amazing 27.5 MPG on the highway! I was in total disbelief!!!

On a minor note, i'm gonna be down in Hilton Head this whole week....any of you live around here? I'd LOVE to meet up with some other SCMC owners in the Carolinas while i'm down here!

:thumbsup:

nckissfan
07-03-2005, 11:13 AM
Hilton Head is beautiful, have fun!

jsnake
07-14-2005, 06:53 AM
My 98 Has gotten 25.5 on the highway and 17 in the city since it was new. I just put on ford shorties and Bissani with a x-pipe and it seems to be a little better. About an mile per gallon in the city. Also I had a computer tune on a dyno. That could have had something to do with it also. My low idle rpm has picked up since to 1000 or a little better some times, Anybody know how to lower the idle? The manual says not to mess with the screw on the throttle body.

ausie
07-17-2005, 11:05 PM
The throttle stop set screw is only used to set the throttle plate closed position. Attempting to adjust the throttle stop set screw would probably increase the idle speed. It is the IAC solenoid valve that controls the idle speed when the throttle is closed. Typical idle speed is about 800RPM to 1000RPM and it may be as high as 1200RPM when the motor is cold. If your idle is beginning to creep up, you may want to clean the IAC since the pintle (shaft of the solinoid) does grime up a bit after a while. You should probalby use electrical parts cleaner to clean it since some throttle body cleaners will attack the varnish used in the solenoid windings. Also the PCV valve also adds to the idle speed since the PCV system pulls in air throught the motor from the intake. Cleaning the PCV with throttle body cleaner will free up the check valve in the PCV.

jsnake
07-19-2005, 06:53 AM
I took the IAC off and sprayed it with WD40, but it made no difference. 'll try the PVC valve. Thanks for the info. :thumbsup: