I have a 93 z28 six speed that I had just traded for about 4 months ago.When I got the z it had just had a new water pump put on it.It had a problem when I would floor it ,after that it would die on me sometimes,but it never failed to start back up for me,sometimes it took some cranking but it would start and it was also burning rich.I was told it was the opti-spark being that the water pump had went out and was not replaced at that time.I priced it and about choked!!!I also had heard that MSD was soon coming out with a performance opti-spark so I was kinda waiting on that and hoping that my car would too.Anyway I decided to change the computer in it one day and it fixed the problem and seem to add about 50 horsepower to it.It ran like a scalded dog and recently I had bought a cold air intake off of E-Bay,not a name brand but it looks nice on the car and seems to add about 15 horse.My car was running awesome for a while,good enough to get me a ticket!!!!Then about 2 weeks ago it started to break up on me at four grand,it runs fine untill then and then you have to floor it to make it break up and it seems to be getting worse now it will break up at around 3 1/2.I have had the chip in and out of it a couple of times.Could that be the problem or what?If there is anyone out there tat might could give me any suggestions or refer me to someone on here that could I would appreciate it!Before this problem the check engine light was on,I had a test run on it and it pulled a (Quad Drive Fault 1) I beleive it was a code 26.Does anyone know what this means,it was running fine then but it might be the accessor,I dont know Please help I want my horses back.I cant afford to have it fixed so I will be doing it myself but I dont know where to start and stop!E-mail me at ricky0598@midtnn.net or on ls1tech.com I am Zero28secGone.....Thank you

 

i dont know the 93s codes, but from what your describing it sounds as if you have a bad plug wire or coil or both. how many miles are on this car or the wires in particular. what about the coil? how many miles? first thing i would do is pull the wire off the coil that feeds the opti spark. check its condition. just in case its bad have new wires already or another car to get you to the parts store. if it seems fine. has good flex to is and is not brittle. then try swapping out the coil. have a friend with a perfectly fine running LT1? swap coils with them real quick. its not hard to do. see if that fixes the problem. i find that a lot of the times high end break ups are from a coil going bad, but it could be the opti. if it turns out to be the opti call jason kromer down in florida. i dont have the number, sorry. however he will sell you GM optis for cheap. im sure someone here can get you the number to the dealership he works at.

 

high rpm stumble, could be opti, coil, wires, plugs. Make sure you dont have any burned wires, etc.

 

What they said, check the easy (and cheaper) stuff first. Wires, plugs, coil, ignition module etc. Do you have headers on it? If so then I'd bet it's plug wires, especially if they are the stock ones. Here's an easy way to check plug wires, raise the hood at night with it running and look for sparks and arcs flying about, sometimes you can hear it arcing too. Also, I think all MSD has right now is the cap and rotor. If you do end up replacing the entire opti then be sure to take the cap off the new one and put loctite on the screws holding the rotor on or you will be taking it apart again in the near future.

 

See my sig for the 93 codes and troubleshooting.

 

I would bet opti but check the other stuff first

 

Thank you for all the suggestions I have replaced the coil already and still have the problem.I thought about plugs and wires but wasn't sure ,the wires look old .What plugs and wires do ya'll suggest and no it does not have headers yet.The car has about a 113000 on it, if possible could someone get me Jason Kromers # please,just in case I need an opti does anyone know if opti are rebuildable ? I was told that you had to pull the water pump to replace it is that so? This is my first LT-1 and I heard a lot of bad things about the opti spark . Do they have a rotory button and cap like older chevy's or what? So you guys think it is something simple and not nothing serious ? The computer going bad has crossed my mind, I will try this things and hit yall back up later.Zero28secGone is out thanks

 

It is almost always the opti