M50 Idles Bad

[jeds320i]

My M50nv isnt running right, I swapped one into my E21 awhile ago. I've been trying to figure out whats wrong and cant figure it out. I've replaced/checked just about everything. I just put new intake gaskets on and new vac lines and everything. I dont have a vacuum leak. My fuel pressure is 43 psi or so, spec is 51 psi. i just put a brand new pressure regulator on too.. When its idling i clamped the fuel line before and after the fuel rail to make the fuel pressure raise and lower. Didnt help. I have no idea whats wrong.
Here's a video:

http://www.youtube.com/watch?v=0GLtHNtkNFo

[luis.e30325es]

make sure throttle cable had slack on throttle, may be a dumb suggestion, but on my swap there wasn't slack, so my engine's idle was going up and down like yours, only higher rpm's.
just a thought.

[jeds320i]

I tried loosening the throttle cable, didnt help. On a cold start up, itll run fine at like 900 rpms for about 2 minutes, then the idle slowly starts to get crappy. And after its warmed up it sounds like in the vid. Ive tried everything. Whats the fuel pressure supposed to be?

[jeds320i]

BUMP

Like I said, on cold start up it'll idle fine at 900 for about two minutes. Then slowly starts to get rough. It sounds like it starts knocking real bad or something and shakes the whole car. What could be wrong?

[nwe30]

my m50nv had the same problem. it ended up being the maf sensor. let the car sit and cool down. unplug the maf, cold start it, and let it sit for 5 minutes. i guess the ecu stays in "warm up" mode for a couple minutes and unplugging the maf is supposed to keep it in warm up mode. don't touch the throttle while the maf is unplugged. if it idles fine for the 5 minutes, it's your maf.

what about your icv? is it responsive?

[jeds320i]

I thought it was the maf too.. I unplugged it while idling and it didnt change the idle. So i ordered a reman. Put it in and didnt fix the problem. Icv buzzes with key on, im pretty sure it works bc i ordered a new on and tested ohms and everything and it was the same as mine. So i just sent it back obviously. It sounds like it starts knocking at idle, and starts running rough. Like the ecu is makin the timing of the injectors or plugs off for some reason..