I bought my '94 Z28 a few months ago. It currently has 101K miles on it. The one problem I have is after it is at normal temprature it will miss when under load. say after I make 1st to 4th gear shift (cags). If I give it to much throttle it will miss Intermittently. I have replaced plugs, wires and coil. Is this a symtom of a bad Ignition control module or do I need to start looking for a new opti-spark?

Thanx

 

Either the ICM or opti can act up because of heat, so it might be a little hard to track down. Chances are it is the opti, if it is the original with that many miles.

 

I believe it is the original. Is their any way to tell for sure. The Helm book doesn't seem very helpful.

A couple other questions.. Since I might have to replace the opti-spark would it be possible to to convert everything over to the vented from '95's and up? If you can, would the upgrade be worth the trouble?

 

Anything intermittent and especially the opti is hard to diagnose.

If you are up for a cam swap, then the vented is viable, IMO. There are many things you have to change, though. Just to swap for the sake of going to vented is costly. There are guides on venting the non-vented ones, too.

Info on swap:
http://para.noid.org/~muttvette/opti.html