I have an 88 iroc, and I get the service engine light every once in a while. I put the key into the diagnostic connector and it says code 33, which means the MAF. But i already replaced that, the gasket for the throttlebody, and all the PVC lines. Its driving me nuts...what else could it be??

 

The samething happened to me. I ended up replacing both relays. There is two of them on the driver side firewall. It could also be a loose wire or plug on either the MAF sensor or the relays or both.

 

I was thinking about that, but I never got to them. And also the little black accordian thing the PVC tubes are hooked up to (vaacum) I might have thought becayse everytime I pushed it in a couple time it seemed to run good for a couple days.