2004 Pontiac Grand Prix Q&A
2004 Pontiac Grand Prix Question: rpms go up and down when idleing
The cause of an idle surge can sometimes be hard to pinpoint. A sensor could be failing but not enough to turn the check engine light on. You may have a dirty throttle body or a fuel injector issue. This problem may need to be checked out by a qualified technician. If you don't have a regular shop that does your repairs check out the listings at www.repairpal.com. - Russ
I had the same problem with my car start about 2 months ago and thought it was the O2 sensor as well, but it turns out it was the mass flow air sensor instead. - Visitor
When I am idling at a stop, I can watch my rpms go up and down. I can also feel the car almost sputter out like it is going to stall out, but then it "kicks" back in with the engine sort of revving...
when you start the engine it idles fine for 2 to 3 seconds then shuts off. if you rev the engin...