zabranca

Hello all,

I am having strange misfire then smooth running cycles on my 1.8t. The car will frequently have trouble starting and when running seemingly runs on only 2 cylinders. Very rough and shaky. I verified this by unplugging the coil packs one by one to listen for any engine variation. I have swapped plugs several times and have exchanged a number of old coil packs for each cylinder. If the car runs roughly for long enough it will smooth out and purr as normal. If I apply some rev's to attempt to take it for a drive it will again resort back to sporadic misfires.

This problem occurred pre and post head gasket replacement. No codes from crank or cam sensors. Fuel pump or injectors? Why would it run smooth for a bit if either were bad? I suppose it could be the fuel pump because the car struggles under load. Forced readiness check revealed fuel system ok though i'm not sure the fuel pressure is evaluated.

Any help would be greatly appreciated. Thanks!

zabranca

Also worth noting:

Throttle body adaptation
Removed MAF plug before and during running - no change
Good compression in all cylinders
Checked for vacuum leaks, nothing obvious or any problems I could find

Some are saying crank case breather/PCV system?

Thanks