I've found over time that low rpm missing is usually (but not always) related to a spark/iginition problem. Ends up being a plug worn to a very high gap, carboned up or fouled in some way, or a loose ignition wire/arced cap, cooked wires or something allowing the plug not to fire. Plugs are so cheap if I see this anymore I just change them and cure this most times. If it's fuel injected could be a dirty injector. The quick and easy high probability fix is:
1. New plugs (look closely at what comes out)
2. Can of Injector cleaner
Also, an easy check if you have an inductive pickup timimg lite is to keep it in the car, and when it does this, place the pickup on each plug wire in succession. If the wire (typically carries 15-30 KV) loses spark...the timing lite will blink (dark), quite noticeably. An easy way to troubleshoot the high tension side without taking anything apart.
I bet new plugs and/or a can of fuel injector cleaner solves it.
[This message has been edited by djenkins2 (edited 10-29-2000).]