elanstyle

Have a 09 Q5, with 2.0 TFSI. Car has recently developed an issue of covering spark plugs in carbon (black plugs - dry) which causes misfiring (Annoying). Have changed plugs, and still has same issue. Have swapped PCV, and swap coils, and no result. The weird part is it does not do it to all 4 cylinders at once - only 1 random cylinder at a time. It will do it to cylinder #1, and I change/clean up the plug, drive another 20-30 mins, then it does it to cylinder #4, repeat process, then it does it to Cylinder #2, then Cylinder #1.. and so on.

Car uses oil like every 2.0 TFSI of this age, and it also slipped a tooth on the cam timing 6 months ago, but it has been still happily driving around without too much bother (just down on power low down) until now.

Any suggestions as to fix this carbon issue on the plugs ??