dw9893

Sorry - I tried to read all the back posts as requested and really couldnt find my unique problem, but I tried!!! Anyhow.. here's the problem.. but I probably figured it out, I just want some people's opinion, or maybe some information that will lead me in another direction that I never thought.

Problem: For about 10 months my engine light was on.. and I knew why.. I had it diagnosed and the code translated into incomplete o2 circuit. My mechanic told me that usually comes up when you drive off the gas station and leave your cap undone. Yes.. Its embarassing, and its only happened ONCE mind you.. and sure enough I had done that very thing not to long before the light appeared. Well seeing as it wasn't near time for inspection, I obviouslly <knowing the issue> let it go. 10 months later.. the light goes out! But.. smart me takes a glance down at the lights on my panel as I start my car, and they all pretty much stay on for 2 seconds and go away, but the engine light is not one of them..

Question.. Did my bulb just go out on the engine light.. OR - did it really clear itself and won't be a problem from here on in.. I just wondered if you smarter tech people with mustangs know what lights are supposed to come on and for how long during the ignition sequence for the car.. Its a 2001 Coupe.. nothing special, no mods..

Thanks for helping

pichinco

If it never came on...it's burned out.

The only way to know if the code that was causing the problem cleared is with a handheld. Usually the "cap off" syndrome will clear itself shortly after restoring the cap. Surprised it didn't. I'd be sure you don't have other problems as well.

midnitestang

My check engine light on my 98 GT and I took it and had the codes pulled and it turned out to be the same problem your describing. I ended up having to replace the gas cap. You might want to try that after you replace the bulb. Its a cheap way to start

dw9893

I will have to get that checked then. My friend told me they do a free error code reading at the local Autozone, and that makes me happy, so I guess tomorrow I'll go in there and check it out, I thought if it didnt come on during ignition for a few seconds like the other one that it was probably burned out.. I mean come on.. it has been on for 10 months! Lets hope that it doesn't lead to other problems. I do baby the car.. after all it is a Mustang.. so I can't really think of what it could be. I need to replace the plugs, but other then that I've treated her well.. No missed oil changes, I've replaced the brakes, did all the other engine maintenance I can think of.. had the hoses - belts replaced, flushed the raidiator, did a total fluid exchange.. checked all the other fluids as well.. replaced the cooling system. I didnt have to do that, but living in Texas come summer it will be worth it as it sure taxes the cooling system for 3-4 months straight on high at as freezing cold as it gets.. I've had the car for almost 3 years now.. so replacing it once will be worth it. I have had other work done to it too.. so for 3 years old almost.. it shouldn't really lead to other problems.. or I hope not anyway.. Can't have my baby dying. Thanks for your input though..it helps me.

dw9893

Thanks! I will have to try that.. I never would have thought of that in the first place.. you think its a bad cap then? I never would have thought that for being only almost 3 years old. I've put a lot of miles on that puppy since I got it. The car is actually only more like 2.5 years old.. I got it in late '01. But after 2.5 years and over 80K miles.. I guess it could really be a bad gas cap.. after all I did have to put all that gas in it.. Oh hey that brings up another question.. I have the stanard v6 coupe.. and I was wondering if you know what kind of mileage I should be getting to the tank.. It seems like Im losing some mileage.. and I've done all the standard things you should try.. I even got it a K&N Air filter.. who knows - maybe thats a problem... but I only get like 275-280 miles to the tank.. and its a 13 gallon tank. I hear some people get 350-375.. If you know anything... I also get regular changes for the oil, clean out that air filter.. as I said in the message above, the really only thing that needs to get done is chaning the plugs, but I do that every 20K miles or so, and Im using the standard .054 gap.. maybe there is a better gap that will get me better mileage?

pichinco

Actually 275-280 sounds about right. Your not going to do much better than 20ish miles to the gallon. 375 range on 13 gallons would be nearly 29 mpg...ain't likely to get that out of a Mustang GT even running all highway. I'm not sure the v6 gets that kind of mileage!!

dw9893

Yea.. but I have a v6 coupe, not a GT... I figured I should be getting maybe 25mpg - at least on the highway.. and at 13 gallons.. I figured I should be getting 325 miles a tank..maybe 310 on a bad tank, not 275-280.

roundman

DW, did you ever think it could be that big right foot with the cowboy boot on it mashing the hell out of the go fast pedal? rumor has it you Texas boys like to do a little speeding on the roads out your way because everything is so damn spread out! and running the AC wide open ain't helping you any either! lol seriously, I agree you should be getting more than you're getting and you shouldn't be having to change the plugs every 20k miles either. open the gap up to .056 for a big spark and see if that helps. you may not believe this, but I once got 27 mpg with my 88 AOD on a trip to new jersey on a cool day where I ran with the windows closed and no AC on at 70 mph with cruise control on! then I got to Raceway Park in Englishtown and the first thing I run into is a young guy with a 5 speed Stang bitching cause he don't get but 12 mph with his. I didn't have the heart to tell him about mine! lol

dw9893

Your too funny! - When I had my 2000 GT - I must have gotten 10 MPG because I modded it to all get out and raced it all day long. I don't think with this V6 Coupe I could really beat anyone anywhere.. in fact the other day I could have sworn I saw some go-carts beat me down a hill. Must have been the wind or something. But seriously, I dont really mash the peddle if you know what I mean. I do drive it long distances on the highway every weekend.. Is there some sort of long term care I should look into that could give me better mileage? I will give that .056 gap a try for one, that sounds like a sure bet. I can believe you on the 27MPG.. in my 99 V6 coupe I had.. I got on a road trip and did the same thing pretty much, and got somewhere close to your 27.. I think it was like 26.4 or so.. I was happy. Anyway, let me know if you have some other ideas, Its time for me to change my plugs, and Ill probably wind up doing it sometime in the next month and Ill let you know what happens.. Thanks for the input.

pichinco

Oops!! Dunno where I got GT, guess I just have it on the brain. <grin>

You should be getting 27-29 mpg highway, 20 mpg city according to the EPA specs. Your tank is actually 15.7 gallons of which you probably use 13 before you fill up. So your estimate of 350 is right on, or 260 running around town. Anytime your mileage goes down that much it usually indicates a maintenance problem, but it sounds like your taking care of things. Check your air filter and fuel filter. Make sure you don't have anything plugging your intake. You might also want to take a quick check around your fuel lines. Have you tried any fuel system cleaners? Could be dirty injectors.

The other thing you could try is resetting your computer. Pull the negative battery cable and wait about 5 minutes. Reconnect it and see how you fair. Beyond that it's just checking your OBDII codes and troubleshooting. Let us know if you find anything.