I have had the car for three years.It is a beautiful torchred 96. The first time I had this problem I was sitting at a red light and I thougtht somebody bumped me from behind. The car lurched up and the tach jumped a about four or five rpms. One time I got gas on the way to Savannah for a car show and we thought we had bad gas.The car ran so bad I had to go into a Chevy dealer who drained the tank and refilled and flushed the fuel inj system. One time it started to break up and I drove about 20 miles and it cleared up. It seems to happen when the engine is hot about 225 to 230 sitting in traffic. It happened in Boone,NC and the check enging light came on for a crankshaft positon sensor. The sensor was changed but it did it again. That code has come on about 6 times since. The hypertech program was in and taken out with no difference. We found out at one Chevy dealer that it had a 160 degree thermostat in it and was replaced with a 195 its run better. I was running in NC mtns a few weeks ago and it broke up going up a mtn. while trying to pass a truck.I had the car to Wilmington to National Speed and they did 7 or 8 pulls up to 6500 rpms and could not get it to break up. The tech took it and got it to stubble under heavy acceleration. They want to do a major tune up wires, plugs etc but it was already done at 55000 miles, it has 80000 on it now. I think it is a computer problem because of the inconsistency of the miss, stubble whatever you call it. What does a computer cost and can they be bought. Does anybody or has anybody had this problem. The opti-spark system has been replaced at about 65000. Any help would be appreciated

 

Sounds more like spark related; something breaking down with heat or a heat related bad / intermittent connection.

 

What has to be done with a computer change? Does it have to be reflashed? I am mostly an old car guy so computer stuff is foreign to me. I feel like I am just throwing money at a situation. Can a opti-spark system be tested?

 

Intermittent break up, first thing I think of is a bad plug.

 

Who did the tune up, you or a shop? A couple years back I bought a 93 that the seller said he had new plugs installed the month prior by a shop he used for his other cars. Not long after I bought the Vette it would miss under hard acceleration. I checked fuel presssure, plug wires and everything else except pulling the plugs because the prior owner said the were new. Finally I decided to pull the plugs to see if I could determine which cylinder was missing and to see if a plug was bad. The plugs on the driver side bank were new but when I pulled the passenger side (which is a lot harder to get at) the plugs were original equipment plugs and the electrodes were so worn the gap was almost a 1/4 inch. It was a wonder they fired at all. The shop didn't change the plugs on that bank. Also found that the coil wire was arching to ground. Once on another car I owned I was installing new plugs and I cracked the porcelan on one plug but didn't know I had. Naturally the plug missed and it took me a while to figure out the problem.

 

I recently had a tune up done at a GM dealer and installed new plugs,wires and fuel filter. I asked to see the plugs and wires and found that the car had Bosch plugs which the dealer said is not good for vettes. One of the wires came loose on the opti-spark at the boot. I found when I put s meter a on the wires I had no reading on one of the wires. I cut the boot and found the contact covered in corrosion. Since I did all this the car seems to be running fine. I will find out on Sat. when we do our three hour run to the Marine Air Base for our toy run if it in fact is fixed. Thanks all for the help and comments. Joe Demko

 

These were my exact sympoms when my optispark was bad on my 93. In fact, that's prob why the guy sold it to me!

The only oddball is that you have a 96 which comes w the vented system. Those are supposed to be much better than the pre 95 models wo the vent.

Start w new plugs and wires (don't use the msd gm lt1 wires they are a pos) and if that doesn't fix it then go w a new opti. Make sure the vent is working also.

Heck the wires and plugs are so har pd to get to)unless you have LT headers) you might as well consider replacing it all. Be sure to seal up thd optispark w silicone sealer. Make sure the waterpump isn't leaking onto it either. If it is, then replace that too.

Good luck

 

Pull the codes to confirm. Low resolution codes = bad opti. We sell value priced replacements.