dado12345

So my cylinder 4 has been misfiring slightly for a while (but i didn't know about it since the engine light never came on).. All of the sudden all 4 cylinders start misfiring.. car runs like crap and can barely accelerate..
I replaced the following:
All 4 coils and plugs.. spacing is correct on the plugs..

It fixed the all the cylinders but the cylinder 4. Then i took it to the local Audi dealership and they told me the wiring was bad on cylinder 4, so they ended up replacing it. Now my problem is cylinder 3 is misfiring like crazy. They did every possible test and could not figure out why.. finally after 3 days (I paid 120 for the inspection and it took the mechanic 3 days) to come to the conclusion its "possibly" the ECM, which would cost me 1100 just for the damn computer... I don't want to spend over $1300 just to find out that isn't the problem

PS: sometimes, after driving and beating the crap out of my car due to frustration, the misfiring slows down, and instead of sounding like a motorcycle, and acting like my car has 50 HP, it will run great until I gun it, then it will misfire like crazy, the lower the RPM/the higher the gear, the more misfiring is happening... After i let the car sit for a few hours, back the the same problem.. lots and lots of cylinder 3 random misfire...

Anyone have a possible solution I could try? It makes me real sad to see my TT driving like this.

BTW its a 2000 TTQ 180hp

siegrisd

It would seem likely that if you have one coil pack harness that failed, most likely all of them are going to. With the heat that they're subjected to, the insulation on all of them would have aged the same way and would likely be failing at a very similar rate. I believe that there was a post regarding a similar issue in the old forum that addressed this, but, of course, I'm not sure if that information is available anymore.

At any rate, I would seriously suspect that all of the harnesses have at least some tiny cracks in the insulation of the wiring and are shorting out on the valve cover.

Best of luck and let us know what you find.

dado12345

would there be a temporary fix to see if it would help.. like taping it up somehow.. i think i read something like that on one of these misfire threads.. and i would almost assume that the audi dealership would have noticed something.. or recommended something since the car was there for 3 days being inspected.. it'd be nice if there was a way to get it working now so i dont have to wait for the harness :/ grr these cars are crazy

siegrisd

... but, I can't remember all of the specifics. It was pretty tedious, regardless. It would be a good idea, if you try the tape, to hunt around and see if there is a high-temp tape that you can use (sorry - I don't have a specific recommendation). I'm not sure that regular, black electrical tape will be able to withstand the heat. A nasty goo ball isn't going to get you very far, of course.

aTTeo

Check the plug to the throtle body. I had a similar problem with my TT and I found out it was one of the pins on the male plug. I replaced all 6 pins and the car is working just fine. Good luck