Hey all,

I bought a Q5 3.2 with 140,00 km (approx. 90k miles). I immediately took it on a 1200km trip home, where it drove perfectly (other than the MMI, but I've bypassed the amp for now and its good). I put on probably another 1000km before taking it on another 1200km trip (each way). A few hours into the drive back, I thought I felt misfires on acceleration, but was not sure, could just be bumps in the road. It got progressively worse until 200km from home I went to pass a semi and the misfires were so bad I barely got past him due to no power. As I got past, the car started shaking violently, and the EPC light came on (don't remember if it was flashing). I immediately pulled over and turned the car off. But I had to get home so after 10 minutes I turned it back on. The EPC light was gone and car ran smooth. I babied it ever so carefully home gaining all my speed down hills and losing all of it up hills. This way, I did not feel any misfires. Chucked a cheap code reader on it once I got home and some P03xx codes came up. Misfires on cylinders 2,3,6. Maybe foolishly, I cleared the codes to see if they came back. Driving around town after that, I felt no misfires. I also ran a fuel injector cleaner through the gas tank. I even took it on an approx. 1hr drive a few times to try make it come back. Thought maybe I got lucky and clearing the codes fixed it (maybe reset fuel trims or something). A few months later it was time to drive back to university, 1200km. Again, a few hours in the misfires started coming back. Stopped at a euro mechanic in a city to see if they could find anything, and they said no codes whatsoever relating to the drivetrain came up. They had no idea. So my only choice was to keep driving. I babied that car so much that a 11 hour drive turned into a 15 hour drive. Misfires got worse and worse, I think worse than the first time they came up.

Ive read through many forums and it seems that misfires are often coils, but it seems to also be that people end up throwing thousands trying to chase down the problem. I'm a full-time student, I cannot afford to do that. This only happens with long drives though, that must mean something. If it means anything, I feel that my oil consumption is much much worse on the highway as well. I've never had to add oil while driving city, but have had to add oil on each long trip (except the first). Could this be relevant? Could it be something to do with heat soak? I'm stumped.

Things I have done:
Pulled spark plugs - look fine to me. Only one had the white residue on it.
There was a bit of oil on one or two of the coils, so valve cover gasket could probably use replacing. Could this be messing up coils?
Checked for carbon buildup - I thought it was quite a bit, sent a pic to a mechanic friend and he said it wasn't enough to be causing my symptoms. Also seems to be weird that carbon buildup would only cause misfires on long drives.

IMG_1939.jpegIMG_2014.jpegIMG_2013.jpg

Appreciate any input!
- Curt