My '92 Accord LX has the same issue and has had the same issue since I bought it in June of '99. I've had valve jobs done. I've had a motor vac done. I've had a compression test done. I used high octane gas. I've used fuel system cleaner. New spark plugs. New distributor. New wiring harness.

I don't know what else to have done on it and I still have the rough idle. It seems like the RPM when idling (worse when she's in gear) is too low because, as the original poster said, once you step on the gas it smooths right out.

I don't have the jumping RPMs though. It happened once a month or so ago, and never happened again.