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

 

Few questions though that we need to know first. What kind of spark plugs do you have installed right now, along with the brand of coil packs? Also do you have a boost gauge? Also is there anything that has been modified on the car? Have you changed out your coolant temp sensor to a green top one?

 

Yes, the coolant temp sensor has been replaced to the green square looking one... make of the coil packs/plugs, i have no idea. The first set i bought was from advanced autoparts, it didn't fix anything.. so i retuned those, put my old set of packs back on, then i bought another set from the audi dealership.. the original ones.. and it's still doing the same thing. The plugs I ordered online off of ebay (don't give me ****! lol) then made sure the spacing is at .032.. and the dealership also looked at it and confirmed the plugs and coils were working fine..

there have been absolutely no modifications done to the car... I just got a new clutch put in it but it's been doing that before the clutch was even installed.. now its just even worse :/

sorry for the late response.. been a long day

 

Bad gas maybe, other than that, I have no idea, I wouldnt think that the ECM would be going out, but then again I am not a audi mechanic, that is crazy.

 

Well. I have pretty much same issue. I thought ignition control module is in ECU on this car so it is technically possible that ECU isn't doing well especially if you had damaged wiring like the dealer told you (same thing on mine). Also is 0.32 i right gap for stock TT?

Anyway I guess I found a dead coil pack on my car. Will see if it will fix the problem once i get the replacement.

 

Isnt there a couple grounds on the heads for the coil packs? I'd remove, clean, and reinstall those making sure they are good and snug.

Also, did you check the plug wires?

 

I had a hard to find one recently. Turned out to be the fuel injectors not being seated properly. There are a couple of plastic inserts that the fuel injectors sit on. These crack and leak. Try starting the motor, spray carb cleaner around the injectors and if you have a leak the rpms will change.