Hey guys my 95 z28 a4 I's still missing here are my upgrades and what I have changed and test i have done.
New parts- Coil(MSD streetfire),cap n rotor,wires,plugs( the plugs are clean and white since they have been on the car for less then 2000 miles)
Tried moving the injectors around to see if it was one of them that was bad, i also changed the cups and o-rings
Put a new egr I'n
Tried unplugging the O2- no change
Performance upgrades- CAI, Pullies, cat delete
Has an exhaust leak but always had it since i bought the car and back then it was running fine.
Any ideas on what to check next? ( i will be doing a compression test on sat) btw the heads were recently done by previous owner.
* the missfire gets worse as the car gets up to temp

 

Have you identified the problem cylinder/cylinders?

 

yea its either 6 or 8 its a poppin sound coming from the back passenger side

 

the rpms stumble so i know its a missfire

 

Sounds to me like you have a loose plug. Had a friend of my sons think he had a lifter tick. Turned out to be a stripped plug hole.

Do you have headers?

 

Try unplugging each injector wire while running. if you engine stumbles when one is unplugged, than you know the unplugged one is good. if there's no change, than you found your dead cylnder.