strange running issues

[dp2275]

Did m50 swap 2 weeks ago. Ive been running the car up and down the road here and there while i sorted little stuff out (shift linkage, exhaust, etc). Its been running GREAT. Tons of power, etc.

Finished the exhaust yesterday, ran the car up the road and back and parked it at the driveway... I let it idle while i was looking things over and out of nowhere, a funny sound started coming from the front of the motor that sounded like a "hollow tapping" (sound was around the vanos unit or down around the pulleys). Sound went away after 15-20 seconds but the motor started missing pretty bad and almost stalling. Lost alot of power, and while itll pull into upper rpms, its not nearly as powerful as it was.

I pulled the coils and 2 of the plug boots were broken so i replaced the boots and plugs. Car doesnt miss AS MUCH, but its still pretty bad. When its cold, the idle drops down to like 300rpm and then itll bounch back up for 20-30 seconds and do the same thing again.

Ive checked:
-vacuum hoses
-fuel pressure
-new plugs/boots
-bore scoped the cylinders, nothing out of the ordinary
-compression test
1) 210
2) 210
3) 210
4) 210
5) 205
6) 210
-checked all of the sensors
-cleaned icv
-cleaned maf sensor

As you can see, everything SEEMS to be ok but still running like crap. Any suggestions?

motor has AA software, m3 cams, bimmerworld intake elbow, ebay headers, free flowing exhaust if it makes a difference..

[dp2275]

well that appeared to be an easy fix.. the plastic part that plugs into the intake manifold from the icv had popped out just enough to allow a massive vacuum leak. i checked it but couldnt see it well enough apparently until i pulled the entire intake manifold off. i ziptied it like everyone else does and it seeems to be staying seated nicely. the weird sound from the front of the motor was an idler pulley that just took a shit. seems like shes back up and running well.