Hello everyone, I know this is long but bare with me, just trying to provide most details that i can for you guys, and i didn't just come here for help without doing any research or trying things already so anyway, I'm new to this forum and am trying to solve a common problem (so i have been reading on this car). The car has been misfiring for awhile now. It is not my car, it is my friends, just trying to fix it for her to save her money. This is my first audi that i have worked on, aside from an oil change on an a4. Anyway, to the point. It is throwing the p0300 random misfire code. I have checked the coil packs. I found the one i believed to be bad. Pulled harness off while idling and it was the only one that didn't affect the idle at all. So replaced it with new coil and no difference. I take it to audi, have it checked, and its misfiring on #2, which was the coil i replaced. So i played around with it some more. Injector is fine. No other DTC's. What else is scaring me, is that that coolant temp sensor was bad and no check engine light. Coolant temp was always reading 0 degrees. replaced it, gauge on dash works now so there's one of the cars many problems out of the way. Spark plugs are fine, she does put 87 in the tank. Most cars it doesn't effect if they recommend 91 but the car is expensive so you probably have to put the best of everything in the damn thing. I'm stumped. Hopefully more sensors aren't bad and still not throwing a code. Any input would be greatly appreciated. Thanks in advance
Cameron

UPdate: p0300 is now gone, now have p0302 cyl 2 misfire. Will run compression test on that cyl to see what the numbers are.
Update: Compression test on cyl 2 read 150. Seems pretty good to me so i've ruled out compression, spark plugs, haven't actually tested resistance on injector yet. Kind of a pain to get tester leads in there which i'm sure you guys know.

 

I won't "bare" with you...but I will bear with you. There was a TSB for coil packs on the 2.7T, but I am not sure it goes back to 2001. You may want to call an Audi dealer and ask. If you replaced the coil pack and the problem remained, then it is probably not the cp (another way to check is to swap it with a working cp and see if the problem moves). The next obvious suspect is using regular gas. The ecu may be adjusting the timing so much to compensate (and avoid pre-detonation or pinging) that it occasionally misfires. Bite the bullet and run a couple tanks of premium. Even midrange is better, but a couple tanks of premium should allow the ecu to re-adjust and maybe solve your problem. BTW, I generally run midrange or at least alternate fillups between midrange and premium in mine and it has never thrown a CEL.

 

I already contacted the dealer. The TSB does not cover this car. I will try putting 91 in it. But its odd, after i swapped coils, i hook my laptop up to it and now it says p0302 cyl 2 misfire. I dont think low octane fuel would cause just one cylinder to misfire. I can see it causing random misfires but i could be wrong

 

That's a good point -- you'd think "pings" would move around. Then consider the primary elements of ignition for a single cylinder: spark plug, ignition wire, and coil (and fuel/air mixture). Holding everything else constant, you can try swapping each one out with a known working part. If the problem moves to another cylinder or stops occuring in #2, you probably found the problem. If that does not work, then I'll leave it to the other diagnosticians on the forum. Good luck and let us know what you find.

 

Im havinvg the same issue. Missfire on 2 and 4. Replaced coil pack, plugs and wires, but still missfiring.

 

i bet its the ignition control module or ICU-they call it diff things..I had the same prob, replaced coils and plugs..no fix..THere are two of these for the V6-Both on top of the airbox, one for each bank-switch them out to see if the problem follows..For example, misfire on cylinder 3, should follow to the other side, cylinder 1 I think..They cost like $250 at the dealer..Hope this helps..
PS..they are located kid of diagonally to one another...Looks like kind of like a computer chip with a connector on each side of it...(sorry, I dont know the technical terms..)

Let me know how you make out, if you still have this problem

 

Also check the fpr "fuel pressure regulator" and the vacuum hose to it I had the same problem it ended up being tiny pen hole in it changed it and the random missfire went away

 

Hello - If anybody is still using this thread, the video below goes through the three most common causes for the 2.7t misfire! Hope this helps!