2003 A4 (B6) 1.8T TIP 130k Quattro wagon AMB
Bringing a neglected car back to life.

ROUGH IDLE and POSITIVE AIR PRESSSURE at valve cover (oil cap rattles pretty hard if you loosen it)

I’ve replaced the timing belt, water pump, tensioners, serpentine, thermostat, etc.
Completely went through the vac system with a fine tooth comb. All lines are clean and no leaks.
I replaced the spark plugs, MAF, fuel filter, DV, PCV, PRV and CTS
Installed known good coil packs.
Fuel rail was a mess and most wires had cooked and cracked. Fixed that.
02 sensors checked out fine on VAG
I cleaned the TB and did adaptation.
Leak-down and compression checks were great.
No CEL’s
I have not replaced any “N” valves or fuel injectors.


What have I missed?