Coheed

Okay my friend's car looks like a diesel. Anyway, he has thick black smoke coming out of his exaust. I unplugged his MAF and the idle smoothed up but the car won't rev over 4,500rpm (limp mode i believe). Anyway, the idle does clear up a lot when i unplugged it. When the car is first started in open loop it runs like crap. Then as it goes into closed it smooths out a lot. I think the reading on the MAF is bad because when the engine goes into closed loop it monitors the O2 sensor instead of the MAF am i right? Anyway and info would be appreciated.

Coheed

i guess it could be the o2 sensor too but the idle smooths out alot when the MAF is unplugged.

Coheed

Well it turns out it was the MAF. A metal piece inside the cone filter fell off and clogged the MAF. :dumbass:
But it wasn't me, it was my friend's. Anyway, that was the problem, motor runs strong now.