I have recently noticed a bit of a misfire on my AGU 1.8T when the engine is up to temp. It would only last a few seconds at low revs (ie 30mph in 3rd 40mph in 4th etc) but then clear itself over 3000rpm. However, driving to work today it started misfiring constantly and would not clear. I pulled over and disconnected the coilpack plugs one at a time. No.1,2 and 3 made it alot worse but No.4 made no difference = misfire cylinder 4. I swapped coilpacks 3 and 4 but still had the misfire on cylinder 4. The same with the plugs, swapped 3 with 4 and the misfire is still on No.4! There is fuel from all 4 injectors too but this was only a visual check. I called the AA and they had a look. No fault codes present. He said he would put it down to a mechanical failier ie follower sticking, valve problem etc etc. But surely this would mean the car would misfire all the time and not only at temperature, right? Any ideas?
Now the car has cooled down again there is no misfire!?!?!