What could be the culprit causing an H22 to idle at about 3000 to 3500 RPM? When we first fired it up it was idleing at about 2000 RPM, then sometimes it would fluctuate from about 500 to 2000 and keep doing this. My buddy took it for a rip and when he got back after about 5 minutes it was idleing at 3500 RPM. The O2 sensor wasn't plugged in because he hasn't bought a header yet so it just had the first half of the header bolted onto the head.

I've driven my car without an O2 sensor and it didn't make it idle erratically like this so I didn't think it could be caused by that. He talked to a couple buddies of his and they told him that it could be the O2 sensor causing it though. The car wasn't throwing any codes at all(except for when we unplugged the O2). It's an 01 Euro R H22 still running off the OBDIIb ECU.


__________________