ajspellm

i have a 96 mustang gt with 49000 miles on it and i was just driving it tonight and the check engine light came on. the car still runs fine and everything but i have been getting bad gas mileage. i have gotten between 13 and 16. the car does not sputter or anyhting when i drive it either. i have had the car for about 2 weeks and have not had any problems with it before this. my friends think it is an o2 sensor. what do you guys think the problem is?

maddash

Take it to autozone or find someone with a code reader.

02StanGT

Have you done a tune-up lately? New plugs, wires, fuel filter. If you want to know what the code says go to auto zone they read em for free.

ajspellm

no i just got the car from a kid who works at a jiffy lube so i think he might have kept on that. the car is in great condition.

PipsBlackStang

I would say O2 sensor. Advance Auto has a handheld OBDII scanner for like $100 or somewhere around there. I bought one about a year back and it'll pays for itself in just not having to pay someone to look at it. 96 is the first year of OBDII so make sure you get a II. It will come in handy and its always nice to have because even if your car is running fine you may have a friend with a check engine light on and you can give them a free scan and then do the work for them and make some cash.

ajspellm

i drove my car to work today and i went out for lunch and as i was driving the check engine light turned off so i think it might be fine now. shoudl i still take it to a place and get it checked out?

Jglisson

Usually those symptoms are indicative of a Delta Feedback Pressure Switch. A little doo-dad that doesn't cost that much. It assists in proper control of emissions and works off of the EVAP system. If you get a chance to read the code, let me know what it is.

Should be a P4301 if I recall correctly...or is that a # 4 misfire.

Regardless...let me know. A fuel injection service will help clear the EVAP system a bit.

ajspellm

will the code still be there even though the light has turned off?

04BlueGT

I have never heard of a light going off by itself. That's odd. My '04 stayed on until I cleared it. As for whether or not the code is still there, I don't know. On mine, the codes come in two stages. One: flashing MIL means code detected for the first time, but not repeated. Light goes off, but the 'pending' code remains. Two: Solid MIL means code detected two or more times. Light stays on until cleared, even if problem is fixed.

My guess is that the code is still there. I wonder if your MIL bulb is burnt out? Anyone know if it is a small bulb or a LED?

Jglisson

A lot of misinformation out there.

Actually, a CEL will go off by itself. It happens quite often actually. The code will stay as a pending code unless the problem continues to occur. The trigger limit before a pending becomes a hard code which triggers a CEL varies by individual systems, but regardless, you probably still have a pending code that may be read. Even a hard code will disappear if the all systems begin operating correctly. A hard code are usually stored for around 30 miles if all systems are cleared. Some hards are set so that it does take a reset, once again it depends on what triggers the fault. It also depends on whether or not a frequent pending may keep the hard code on file. Most EVAP/EGR and a few other emission codes will turn a hard code on and off depending on engine temp, weather conditions, fuel quality, etc.

A flashing CEL does not necessarily mean more then two pendings have been reported, but that a code has been reported that is serious enough to warrant immediate attention (so Ford thinks so anyways). Even a multiple cylinde misfire may not throw a flashing CEL. However, an enhanced code often will. They want that car to the dealer!

I would venture to say that you still have a pending on file. Hook up to a scanner and see. You can buy a cheap Actron for under $50 now at Autozone or Advance.

Any of that make any sense?