I picked up a 93 Z28 a couple days ago for something to tinker with. It ran decent and had a hesitation off the bottom but after I washed the car and washed some oil off the engine, it was missing so bad it would hardly run. After I let it sit over night, it is only missing on one cylinder now. After reading on this site I suspect the opti but im not sure how to tell. Im hoping what ever it is will dry out and start working for now. Another problem is the guy I got the car from said the engine was from a 98 vette. I can see where they pulled the motor and it rubbed the cowl but I believe it is the original engine. Is there an easy way to tell if it is from a 98 or its the original 93 engine? I dont want to get the wrong opti when I change it.

Thanks in advance!
Shawn

 

You messed up your opti!!!! This is why your missing!!

 

98 would be a LSx engine.... 93-97 is LT1.... Do you have a MAF sensor???? And if you have an OPTI, then it probably got water logged... Just needs to dry out..

 

There is no MAF. I didnt really think the engine had been changed. Will the opti dry out and be ok? Should I change the system to the MSD vented type or just not get this one wet?
Thanks!

 

Give it a couple of days to dry, then see if it starts and runs OK.

 

I had the same problem, well I overflow my radiator and it got the opti wet. I let it dry out for I think three days and I was lucky I did not need to change it out till later.

 

Thanks everyone! I have had it running several times and it still has a miss on one cylinder. If it doesnt clear up in a few days I will tear it apart. Where is the cheapest place to get the parts or should I change to the MSD with the vent?

 

NEVER EVER! Get the MDS Opti, those are a POS! I bought one for cheap off Craigslist new and it only last me half a day. Everyone on here knows that MSD Optis are no good. Its always better to buy a stock GM Opti.

 

Have you scanned it for codes?

 

I havent scanned it because I dont have anything to scan it with. I would like to get something to run off my laptop but I dont know anything what to get. I would like to get something that will work on OBDII as well. I am open for suggestions because I need to get something.

 

Since you have a '93, you can jumper the pins in the diagnostic port.

http://shbox.com/1/dlc2.jpg

 

Ok I jumped the OBDI port and got codes 26 and 32. I looked them up here http://shbox.com/1/Dtcs.htm and they are egr codes. Will this make the car miss? It is hard to start and idles fine but misses and backfires under acceleration.