The car is a 96 SS. The problems are:

1. Going down the road the car will shut off like you turned the key off. Most of the time it will start back.

2. At wide open throttle, it will miss between 3200 and 4400 but only sometimes.

3. When it rains, it's hard to start and runs like it has a miss.

The new parts I have tried:

2 new optisparks
crank sensor
ignition module
fuel filter
mass air sensor

I have checked:

Fuel pressure. It holds at 45 lbs PSI
Optispark on it now has less than 200 miles

After changing the optispark both times it seem to correct the problem for a very short period of time (6 mths the 1st time and 1 1/2 mths 2nd time)

Any advice or tips would be greatly appreciated

Thanks

 

You could say bad plugs or wires... plugs on the LT1 are a B**** to change but with a good chunk of time and the right tools and a little help you can do it. Ummm Ive been through 6 optis so far but now the motor is out of the car and in the shop getting a full rebuild. For me some optis went quick some lasted 10,000 miles or longer. See if your water pump is seeping? Try replacing the water pump. Also check the three seals in the timing cover. Those also seem to offer up some problems, especially the one behind the opti. You also might want to look into a new coil.

Try these ideas, im sure some other guys can give you some deeper insight in to the problem.

Does the car throw any codes. I have the GM service manuals for these cars so if you need a particular section let me know.

 

check the ground in front of the battery beside the alternator its always loose and check ur pcm gounds while ur checking also do it to the opti,coil,icm short to grounds

 

You should deff. check all the basics before just throwing parts at it. You need to check all the connections going to the sensors. Check for vacuum leaks. Not to mention the spark plugs and wires should have been checked WAAAAY before you even consider throwing an opti on it. Plugs and wires are not that bad on lt1's. Its alot easier than doing a front wheel drive v6.

Throwing parts at a car never fixes anything. I mean hell, you could have taken it to a dealership and spent a couple hundred on some diagnosis and found the real problem and spent less money than you already have and had the problem fixed.

 

Forgot to mention, yes, I have changed the plugs and wires (twice). I have also taken it to the Chevy dealership. They looked at it and ran the codes but they were unsure of the problem. The dealership here is rather sorry. This is actually my old car that a friend of mine currently owns. I will check all the grounds and connections to the sensors. The guy that's working on it worked at GM for the past 8 years and he's confused. Thanks for your input. Hopefully we can fix this.

 

not sure if it helps but the harness from the opti to the main harness to the ecu? I've heard those go bad also. (Not mine yet)

 

Well after you check all of the connections, sensors (and that they are getting the correct readings), verify no vacuum leaks, adequate fuel/spark, and wiring. You may eventually be looking into a faulty pcm. Not saying that is what it is, but after you check basically every other option it sometimes is where you end up. Seems unlikely, but in the end it is always a possibility.

 

What brand opti are you using? How old is your water pump? Any leaks in your cooling system?

 

is the vent hose still hooked up? if its not thats you problem

 

It's a Summit brand optispark. Summit assured me it was produced by GM for Summit. Has anybody had good luck with these?

 

Wrong. Get an AC Delco or Delphi.