1993 chevy corvette lt1

engine is missing at idle, changed plugs,wires

I’d replace the distributor cap and rotor too, and check for vacuum leaks.

Generic cap is $100. GM cap is $400. 8 coils?

Hmm, LT-1 is the victim of an OptiSpark that is anything but Opti!

You might want to read this.


This things are problems, pure and simple. This site can direct you to solutions. Swap for the factory cap and rotor or an MSD unit for about $400 to $500.

Given that the belts, water pump, crankshaft pulley, and a few other items need to be removed to service the cap and rotor, I highly recommend you use only quality factory parts. I’ve seen too many problems with the aftermarket units.

The link by @Mustangman is very informative. If I had this problem and was willing to do a little experimenting first before starting on replacing the opti-spark stuff (which might prove expensive), I’d be inclined to see if a simple cleaning and drying out of the gadgets might work. Remove as much of the opti-spark stuff as you can and let it sit in a dry spot outside in the sun for a couple days, meanwhile clean any oils and/or moisture out of the housing where it resides in the engine compartment. For moisture in the housing, I’d also use one of those things that comes in the box w/cameras, that moisture absorbing pellet thing. Heat it in the oven at a low temp for a few minutes first to drive away any moisture it is retaining. Then put it in the enclosure, seal it up, and let it soak up any remaining moisture in there.

A dropping cylinder is also a possibility along with a dozenish other things. It’s a 93 with ? miles on it so compression is certainly something for consideration.