unstable idle and rev

i have been experiencing this problem where at idle my civics (98 ex d16y8) idle is up and down between 200 and 1000 rpm's (when at running temp) also if i rev and hold at say 2 or 3 grand it will oscelate up and down 300-500. does anyone know what this means. im guessing its a baro sensor or o2 sensor but im not sure.

dave

Weird question, have you checked your spark plugs?
I had a problem not too long ago that sounded similar, and it ended up being my plugs had gone bad. Sometimes it'd start up and idle fine, but when I'd drive it and stop at a light the idle would go way down and jump all around. Just a thought to check out.

IAC Intake Air Control. I'm not sure if your car has one. But a real sparatic idle usually has something to do with vacuum or a sensor reading incorrectly. Check your vacuum lines. See if your intake manifold nuts are secure. They tend to get loose. That would result in vacuum leak and the car would run irratic. Just some thoughts. Hope you get it figured out.

plugs are good (bosh plat plus 4) they check good. still running stock wires because this summer im doing a sci ignition and cap from msd with external coil and nology hot wires. im assuming that this may help stabalize my idle. still dont really know why its all messed up now though. and yeah, sometimes i idle so low i almost stall like what was happening with you.

does anyone know what may be causing this problem? do i need a grounding kit or somthing of that nature?