RPM Jumps

[Yoslack]

I've been having a problem with my 98 boxster at idle my rpm jumps up and down. It goes up about 400-500rpm then go down and jumps back up. It doesn't happen all the time but happens enough. Anybody have an idea of the problem please let me know.

[Tool Pants]

Air flow sensor is my guess. Jeff

[jfmillr]

yeah sounds like a bad mass air flow sensor, could be a bad sensor on the exhaust system. THere are 4 down there too that might cause simular problems.

[Alshig]

Had an RPM jump a few times , then the next day a engine check light. Dealer replaced a bad O2 sensor on warranty.