Hello everyone.I had a 2001 Pontiac Grand Prix GTP, but blew the motor on it. I had it replaced with a newer motor with no supercharger (still a 3800 Series II though). Lately its been idling rough (below 1000 RPM), and I also hear a hissing noise near the MAF sensor. It sounds like an air leak, but I can't quite pinpoint where its coming from. I've cleaned the MAF sensor, and the vacuum tube near it seems fine. There is a black (plastic?) cover on top of the motor (not the one for looks) that's hooked up to the air filter, MAF and idle sensor on the right side. It almost sounds like the sound is coming from underneath that black piece, just to the left of the MAF and idle sensors. I'm not the most knowledgeable when it comes to cars, so I hope you can forgive my lack of technical terms. I can't seem to figure out what's causing the hissing sound, nor what is making my car idle funny. Hope you guys can help, and thanks for looking.
