I recently bought an 02' Chevy Cavalier, automatic, with 70k miles on it. The car idles at about 6 grand. When I'm stopped the car sometimes stutters and the tachometer either jumps up to 7 grand or down to 5-ish grand briefly, and then goes back to 6. It happens at irregular intervals and I am wondering if this is normal or if there is a potential problem that I should be addressing. It seems to only do it when the a/c is on, but I haven't driven it much without the a/c because I live in Vegas and it's been super hot. The car also sometimes revs (when I give it gas) without engaging and then goes into gear when I'm making left hand turns. It's weird. Thanks for any and all info/help.
As far as your idling concern I would not worry to much about it. The A/C will increase the idle when the compresser kicks on and decrease it when the compresser shuts down.
As for the slipping when turning I would recomend that you check the transmission fluid. If it is low it will all slaush to the rightside on those left turns and the filter will not be able to pick the fluid up.