I hope someone can help me. My daughter drives an 95 mustang gt, stock, 5sp, with 122,000 miles on it. The problem is...the check engine light is on but no codes can be read. When the light comes on the rpm's are over the place and it will eventually stop running if it is idling. I have had it to three different people here in the town we live in and the one guy is suppose to know everything there is to know about mustangs and he can't find the problem. He has checked the vacuum and it is fine, we have installed new plugs, plug wires, pick up rotor, pcv valve, and ignition module.

Can you give me any help as to what is going on with this car and what they need to be looking for.

Thanks

 

I'm confused. How could the CEL go off without a code being stored? </P>


I used to have a old Escort GT many moons ago and the CEL came on. I took it to the dealer (back when I didn't know any better) and they told me they didn't know what was wrong with it. I asked them what code was thrown. They told me that the code doesn't get stored and that they could only read what the error was if the CEL was on at the time it was plugged in to diagnostics. I didn't belive him. Anyway, my CEL would come on and go off. So it wasn't on when I was at the dealer.</P>


I have only really dug in to one type of car. The car I have, if the CEL ever came on, a code was stored so you could see what the problem is.</P>


I belive when people tell you they don't know, they only tell you that so you buy a bumch of parts from them to fix the problem. <IMG src=smileys/smiley7.gif border="0"></P>


If a Mustang doesn't keep a CEL then the ECU is useless.</P>


</P>

 

This sounds familiar. We had a 93 F-150 that started doing this at around 150,000 miles. It turned out to be a sensor in the transmission. This sensor caused our RPMs to go all over the place. You would have to push the gas to get it to come down. If this sounds anything like what you are going through let me know and I will ask my husband EXACTLY what sensor it was.

 

Got The same problem. I can start at my house and go about two miles before i will start to have the lack in power. But then it is only in the high ranges, after time (a few minutes) the prblem will occur at lower rpms. And eventally it will be bad enough to where it will back-fire at almost an idle. If anyone else has had this problem, please e-mail me at mailto:jayblanton162@hotmail.com . This problem is driving me insane... Thanks Jay

 

Have your ignition module checked or replaced. It is common for those to exhibit those kind of symptoms when they get hot, but operate normally while they are still cool. The module will not trip a light in itself because its not part of the emissions system, but it could cause other things to register abnormally and trip the light when they are malfunctioning. Auto parts stores can check them, but when they are intermittently bad then it would be hard. </P>


A good way to check is to wait until the car quits running, then yank out a plug wire and check for spark. Even if it has no spark it could other things besides the module, like the coil for example or anything else in the ignition system. It just seems to me that the module is the most likely cause.</P>

 

md..that's one thing..also all these seems to have high mileage without beening there here maybe some other cheap possibilities
1. fuel filter
2. check fuel pressure
3. egr valve
4. tap lightly (with finger) on the mass electictronic see if any rpm if so it's bad
5. you may have an 02 sensor bad (likely with the miles)
6. pull off neg. cable reset 'puter