I had this problem last year and thought I had fixed it. My 89 crx si will sputter at about 3-4k rpms sometimes. Today on the freaking freeway it stalled twice at idle, once when I had the clutch in during a shift and once just idling. Last year I changed the plugs, wires, and distributor cap and things went back to normal. I notice that the rpms drop a bit when I fire up the a/c or put my foot on the brake and that's why I'm thinking its an electrical problem.
Could it be a bad distributor? I didn't think it was the alternator because I don't have any battery problems.

Any suggestions?

 

Any codes?

 

My 92 civic si would do that once in a while until died completely...the igniter it the dizzy was shot. If you look hard enough you can find a brand new replacement dizzy with all components included for around $150...good luck!