I fired up the rebuilt engine in my '89 IROC (the one in the sig) a few nights ago. It's got some problems (namely, it can't maintain a low idle and dies when put into gear), but I'll try to take things one at a time...

As I had it running, I put a timing light on it (remembering to disconnect the tan wire). While the timing mark was rock-steady, I did notice that I had a somewhat frequent miss on cylinder #1 (at least #1, if not more--the pickup was only on the #1 wire, however). Also, I noticed that when it did miss, I couldn't tell any difference in the idle quality either from the engine bay or the exhaust. I would have expected at least a studder or something, but it didn't seem to bother the engine at all.

What would be the likely cause of a miss like this? I should note that the wires, plugs, rotor, and cap are all new; the distributor has been rebuilt.

Thanks

 

if it's an induction type timing light, try moving the light to a different point on the wire. also, check your plugs....if they're good, check all plug wire connections......

 

Good point. Make sure your timing light isn't flacking out on you. Check all cyl's as well - my timing light had a crack in the magnet that made it look like I had a miss.