My car is running horrible it is missing very bad no pick up it is a 95 all stock I just replaced the wires and plugs the originals were still in it car has 80k. Then I was told my cats were clogged so I had them replaced still doing the same thing it doesn't throw any codes it will start no problem will run on highway at 70 but will stumble on a hill or if I give it gas I know the opti goes bad but from all I read a bad opti will make car have a hard start or not start at all I don't mind putting the money in it but just want to fix the right thing can anyone give me some direction please.

 

Could be a weak fuel pump.
Do you know the history of the vette?
How long have you had it?
Depending on that, might think about changing out the air filter and fuel filter.

 

Ive had car about a year it was stored over the winter im in Wisconsin. It was running fine until friday then started acting up I did have it washed but hand washed but I will have fuel pressure checked thx for replying.

 

There are a number of possibilities, but most fall under either the fuel system or the Ignition system. Does the problem seem more engine load dependent or RPM dependent - or is it pretty independent of both ???

Hate to Say it - but it does sound like it could be the Opti. Do a search on this Forum on Optispark problems, and you will see quite a number of people with symptoms similar to yours.

While somewhat unlikely - It could also be "old gas" - the modern gas blends go bad a lot faster than the old pre-ethanol stuff did, so you might want to try running the tank down and getting a tank of fresh gas and see if that helps (I suggest filling the tank - and putting stabilizer in the gas prior to storing the car over the winter).

Since the Opti is both expensive and a PITA to change - you should probably check fuel pressure - a fuel pump that is going (or a clogged fuel filter) could also cause the symptoms that you're seeing. Is the pump noisier or quieter than normal ? Typically a fuel pump that is going will have a hard time keeping up with engine demand - the engine demand for fuel is proportional to the HP being made - so high RPM high load is the hardest time for the fuel pump. High RPM - maintaining speed is not a high fuel use situation - so if the engine is missing under those conditions - it's typically Not fuel supply system related.

If it's not fuel system, it's probably ignition, and you've already changed the plugs and wires, so the "easy" stuff is done (I don't consider plugs and particularly Plug Wires to be easy to change on LT1 Motors). I've seen people have problems with the Ignition Driver module - it's mounted right by the coil, and it's both cheaper (less than $100) and easier to change than the opti - but the opti has proven to be more trouble prone than the Ignition coil driver module.

GOOD LUCK !

 

It's not clear from your original post if the problem started before or after you replaced the plug wires.

If after, I would suspect that either one or more is not fully seated on the spark plugs or the wires are swapped. My car ran pretty well on 6 cylinders when I swapped a couple of wires...

 

Problem was before I changed plugs and wires im taking in to repair shop that I trust to let them figure it out I tried now they can.

 

Or if there is anyone within say 100-150 miles of me that works on them I could bring it to you.

 

Im in Clinton Wi right by Janesville wi

 

Got my car back after about $800 in work done the only thing wrong was I had gotten bad gas car running like a champ now so if anyone's car starts sputtering and loses power but not throwing any codes put some heet in along with good 93 gas and fuel injector cleaner and it might do the trick.

 

I had the same symptons with my 94 C4 - turned out to be a bad Opti Spark.

 

Yea I still have it put good gas in car started running better but now back to what it was doing taking it in tomorrow to have the opti done and hope like hell thats the problem I will post back with results.