So I have a 1992 C4, LT1 6spd, all stock except for rear muffler deletes, and skip-shift elimination.

It was a gift from my father, I was to drive it from Ohio to Texas. I started my journey and it went fine for the first 40 miles, then it progressively got worse, I had to tow it by the time we got to bowling green, 6th gear being completely unusable.

It has hard starts all the time, kicks the starter sometimes, takes excessive cranking (this used to be a one tap one roll start car). When it runs, it clearly has between 1 and 2 constant misfires on the SAME cylinders, at least one is on the drivers side that I know of.

It still gets great gas mileage, unfortunately this is linked to the next problem.

If I press the gas more than 5-15% at any one time in any one gear, it will surge, and just jitter, it will take its happy time gaining 1mph. It tries to die when starting from a stop. This happens cold and warm.

I replaced the plugs, fuel filter, and air filter 500 miles ago, all the wires inspected, all good. Optispark was changed 10k ago along with the waterpump and all radiator hoses. The cats we're inspected and shown to be perfect, the car was never driven hard. The SYS light occasionally comes on, but its fairly rare.

It had a code at one point, 32, which is the EGR valve, but when I went to read it again the next day, it was gone, and it still has not come back, been about 4 days now. This car was always babied and never driven very hard at all, I just want to drive it again

 

Coil? Fuel pressure? Where is the car now? - Jim Van Dorn at Automasters in BG could have had you running again.

 

It's in Waco, TX now, heh. I'll check the fuel pressure today, and the coil has crossed my mind, are there any more reliable/performance replacements or should I stick with OEM?

 

Sometimes a visual check will not tell you the whole story on plug wires. If they have not been replaced in a while I think I would give them a hard look.

 

Don't know how this could happen, but it sounds a lot like ignition timing is retarded, or maybe cam timing.

 

If there is a check code involving a running issue of the engine, the ECM will retard the timing in an attempt to correct the issue. So yes, it is retarded, how much? I haven't a clue, and why, thats what I'm after.

Friday I'll replace the plug wires, EGR, and dist. cap. Possibly o2 sensors as well.

 

I feel I should say I read the codes again a few minutes ago, I have #32 (EGR) and H74? I believe 74 is a traction control code, not sure how the system works or how to fix that though.

 

If the opti was replaced with a non-GM unit, I'd be weary of it.

 

Spark wires in correct order?

 

Possibly the injectors as well? Check the resistance on them if you haven't. Good luck!

 

The GM dealer replaced the Opti with an OEM unit, along with all of the other things. And it ran perfectly with the wires like this, they haven't been changed other than to change the plugs, and I did that one at a time, so its not logical to get the same order, I will go over them again.

 

It sounds a lot like how my 86 is behaving, except for the starting issues. If it is starting hard, and the starter makes a lot of noise, I would check the mounting bolts, and have it inspected. It's most likely the fuel injectors, if it is only missing on two cylinders. If the valve train timing was off or the ignition timing, all the cylinders would be missing. If you haven't done so yet, you can hook up a fuel pressure gauge to it. I think on the LT-1 it should be 42 psi. That's what I would check first. I hope both of us can get our cars running soon.

 

Figured it out. I pulled each plug on each fuel injector 1 at a time while the car was running. I did this to each one around 7 different rounds, to verify and make sure.

The plug on the back of the block drivers side, made 0 change when unplugged. So naturally some would 'assume' bad injector. I went on.

I took the spark-plug out, examined, had gas on it, replaced with a dummy plug. I took the plug wire, and hooked it up to the plug I took out, and grounded it to the A/C condenser and started the car.

It fired 3 whole times, and stopped firing at that plug. The car continued to run as it had been running.

The coil would cause a random misfire, so would the ignition module.

A bad optispark is the culprit.

Waterpump & Opti time, if anyone else has any input as to what else could cause the plug to fire 3 times and stop, please I'm open for ideas.

 

I may be misreading what you are saying. It sounds like you are saying that just one cyl is affective. If this is the case it would be doubtfull if it were a coil or module. If I am reading you right I would install a new plug and wire on the missing cyl before I did another thing.

 

This is correct, it isn't firing on one cylinder. All of the rest work. It is the one all the way back on the drivers side (#8?). The plug only fires 3 times during cranking, as soon as it starts, it stops firing completely.

 

like I said I would start with a new plug and wire on that cyl. being only it is the only one afffective.

 

Alright, fixed my problem. It turns out, when i got the water pump off, the weep hole got too happy at one point and ... 'weeped' all over my optijunk. Therefore, effectively and continuously, destroying it.

Time: 4 1/2 hours disassembly to starting.
Replaced: Water pump, Optispark, gaskets.
Additional: CLEANED, checked hoses, belt, sensors, connections.

So it turns out a bad optispark can cause starter kicks, timing issues, retard the engine, will progressively get worse, can cause false illusions, can make you bash your head into a wall, AND can steal your wallet.

Now, what about that damned EGR code.......