Hey guys, I'm pretty new to the board and these cars in general, but I'm having an issue that I could use some help troubleshooting, and you guys seem to know your stuff, so here goes:

The car is an M6 95 Z28, and after driving for about 4ish minutes, the check engine light comes on, and if just idling at that time, the car almost sounds like it is going to stall, then it picks back up to a fairly normal RPM and sounds pretty much fine. After the light comes on, performance drops a bit (especially up top, theres not that much there). Gas mileage is hurting a bit, even with my slightly heavy foot (I got like 270km on my last tank...about 170 miles all basically highway) and I think that this isn't helping. As far as other symptoms, I've noticed a little bit of an exhaust smell when driving, but I'm pretty sure that is being caused by a slight exhaust manifold leak when its cold (I don't think that would be causing the light to go on).

As far as what I've tried to do so far...not too much, I don't know where to start almost. I had the car into the shop a while ago and he mentioned it was setting a code that had something to do with the air pump, but he never went into details. I checked all the fuses this morning and the Air pump fuse under the hood was the wrong one (25A as opposed to 20A) and it was cooked. I replaced that with a new one of the correct size, and it hasn't blown it, but it hasn't fixed the problem either. When I bought the car he said it needed an O2 sensor, but the mechanic said there were no codes having anything to do with a O2 sensor.

Anyways...yeah, if you guys have any suggestions of things to try or even a place to start looking, anything would help. I'll likely end up taking it to a shop, but I wouldn't mind knowing what part(s) I might need before I get there and they want me to buy one from GM for $1000 =/.

Thanks for your time.

 

Anyone have any ideas at all? I wouldn't mind not having to drive an hour to the shop =(.

Anything would be helpful at this point. Kind of hard to diagnose over the internets, but I offer e-cookies to those who help :-)

 

Even thought the mechanic says it's not the o2 sensors it still may be. My car would run fine until I started cruising at a constant speed and then it would throw the o2 sensor code. When I went to stop it would try to stall out. I would have to keep my foot on the pedal to make sure it would stay running. I replaced them and now I have great drivablility.