Misfire, worst at idle and low engine temps

[gowhari866]

Hey guys. I recently did a valve job and head gasket on my 1995 M3 due to a leaking head gasket and the car ran great for the first few miles but then it started misfiring. It misfires most when the engine is cold, when It warms up it gets a lot better but still misfires at idle. It doesn't really misfire if I am driving while the engine is at operating temp, just at idle. The car has new ngk spark plugs. What do you guys think this could be? The car has 132k miles btw.
Thanks

[Pelican Parts]

Did you check the condition of the coils as well?

[gowhari866]

Sorry for the late response, I was on a camping trip and had no reception. I haven't checked the coils yet, I'll try testing it tonight. Although I don't think it's the coils because it wasn't doing this before the valve Job and head gasket.

[Balthazarr]

Coincidence of something just going wrong is highly unlikely.
If it ran well perhaps something worked its way loose.

[AJLM34A]

Vacuum leak.