I have a 94 Z-28. I recently took it out and baby girl is running rough. I take off at the light and the RPM shoot up high while the car is barely able to get to 40 MPH. After that it’ll shift and she’ll be good to go but it seems like she’s misfiring. I cold started it this morning and couldn’t get her to turn over. I go back outside and just as she turned over she misfired leading me to believe she probably is due for a tuneup which was on my list of things to do. Anyone else have an opinion on what it could be?

Update: After looking through the forums I may have figured it out. I took it through a touch less car wash and read that if the ECM gets wet it could cause your car to misfire and run rough like it’ll need a tuneup. Any actual proof this is the case?

 

Could also be the Optispark got wet or is going bad,I would never take an LT1 car with the Opti through a carwash.

 

This was a touch-less car wash so I figured no harm to the paint. I didn’t realize this common problem could happen. Any idea what something like that would cost to replace if taken to a shop?

 

Well it won't be cheap,hopefully it's just wet and will dry out but a quality replacement will set you back a few hundred plus labor and it's a pain in the *** to get to.
The Opti distributor is located under the water pump and runs off the end of the cam.
The LT1 is a solid motor but that ignition design was not the best,WTF were they thinking?
Get a genuine GM not some cheaper aftermarket,when mine failed on the '93Z I had my mechanic put an aftermarket in from World parts,he said he never had problems with them. It failed in 10K miles, I don't recall what the job cost but I know it was at least $300 and that was quite a few years back.
Prices on Optis are all over the place,labor depend on who does it.

 

Get a Haynes manual and read up. Valuable info.

 

go here and download factory service manual for your year https://www.mediafire.com/?40mfgeoe4ctti problem could be as simple as plugs and plug wires,,, not that plugs and wires is easy,,, lol. are you seeing a check engine light?check fuel pressure. your issue could also be fuel pump failing, yes could be opti or although not high on my odds list could be wet or failing computer. a scan to see trouble codes if you have any would be very helpful. if no codes I would look at fuel pump pressure first.