LT1nitrouZ

I have a 94 Z28 with a 396. Took it to the track, finally got it running decent and on the way home, about 15 miles from my apartment the car started missing really bad above 2800 RPMs (I have a th350, so that is highway RPM).

Now I get in the car, drive it 10 miles, or 15 minutes and the car starts missing so bad it wont run. I thought it was the 02 sensors, but the car misses just as bad in neutral as it does in driving gear. I even tried unplugging the 02 sensors, and that didnt help anything either. I checked fuel pressure, it stays fine once the car starts missing, so its not the fuel pump. I had the Ignition control module tested and it checked out fine. I swapped out the coil with an extra I had lying around, that didnt help. Tried running it with and without the MSD box, that didnt help either.

I would have thought that if it was the optispark that it would run badly right off the bat, and not take 15 minutes for it to stop working, but I cant think of anything else it could be. Any thoughts?

meissenation

iTrader: (2)

Throw a scanner on it and see if you have the optispark error codes.

LT1nitrouZ

only code is a "Lo-Res failure" not sure what the hell that is.

LT1nitrouZ

So did some research on the Lo res code... Guess I am gonna have to suck it up and just change the damn opti.

ALEXZ28

im also having opti problems, are u losing power up top????

LT1nitrouZ

big time... Dropping 80 hp on the dyno from 5400 to 5600 RPMs. Still managed to run a 7.5 at 92 with a super shitty 1.87 60 ft.

If I ever get all these problem straightened out this car is gonna fly.

ALEXZ28

buddy its the opti, mine made 275 til 4500 rpm and dropped to 189. and mines cutting off low end and alot of popping while driving.

LT1nitrouZ

Yeah... I have finally accepted it. I have owned various LT1 cars for 5 years, and this is the first Opti problem I have had... so I won't curse it to bad.

ALEXZ28

i hear ya lol i was sooooooooooooooo pissed when i put the car on the dyno to get tuned on the wide band and it makes 275 low peak power and top end power it would fall on its face. i was like there'sno way this car is making this power

LT1nitrouZ

I was at 385 at 5200 RPMs then it fell on its face... I think if I had a working opti spark I would have squeked out 400 on the mustang dyno... but who knows. I am really not one for dyno numbers. 6 speed is gone now, so I will never know.