My car has a problem no one seems to diagnose?

I've had a similar experience and found it to be a dirty throttle plate in the throttle body. Assuming you have fuel injection, at idle the throttle plate is fully closed with only a minor amount of air being let in through a tiny gap or slot in the throttle plate.

When the engine is cold, air flows around the closed throttle plate by the means of a controlled bypass. After the engine warms up, this bypass is closed. If the dirty throttle plate prevents the minimum flow of air through the throttle body, the engine stalls and cannot sustain running or is very rough.

Get yourself some carburetor cleaner and some clean rags. Remove the intake plenum from the throttle body and open the throttle plate by hand. The plate and the throttle body area around the plate, need to be clean, clean, clean for the best operation.

You can sort of check this issue by watching the engine as you slightly open the throttle plate by hand. If, on opening the plate, the problem pretty much goes away, you can bet the engine is starving for air.

Good luck!

These vehicles are notorious for the optispark distributor mounted behind the water pump for causing problems like this. Check the bottom of the water pump for signs of leaking (Green residue or may actually be wet with coolant) if this is found it is almost a guarantee that the coolant has found it's way into the unit. The water pump will have to be replaced along with the optispark distributor,The optispark units are expensive and not the easiest task for a do-it-yourselfer. I would recommend buying the OEM AC Delco part a lot of aftermarket units are not as high of quality as the OEM and you don't want to do this job again. I would recommend taking it to a shop qualified for this or to a dealership.

Its important too see what kind of smoke is coming out of the tail pipe .White smoke burning water ,head gasket. Blue smoke Burning oil. Black smoke too much gas running rich. regular smoke bad gas water in the fuel. try gas dry. ad a good quality fuel injector cleaner.

if the engine anylzer didn't tell you anything. the timing chain could be streched and you might help it by advancing the timing2 to 3 degrees.

If its an LT-1 did you let it get hot and warp the heads ? those are probably aluminum heads. expensive.

try a compression test. auto zone will loan you the tool for free.

Good Luck ! Superdave

sound,s as though you have a bad vacuum leak ...most sensor & control problem,s would have shown up on the analyzer....although the 94 still had the older computer most good mechanic,s could have found a bad component...but vacuum leak,s can be very tricky...the old stand by way was to squirt some oil on gasket or suspect surface,s while running to see if it get,s sucked in...scan tool,s cannot detect thing,s as manifold gasket leak,s...the LT1 was a difficult one to diagnose...check all sensor & control,s first then check intake manifold pressure , check ignition system , if they yield no result,s have a cylinder leak down test performed...good luck!

If engine runs good cold, rich fuel mixture, fuel system cold start, run not releasing, shutting off when warmed up, Good Luck, Jim.

What Gadget said...

When's the last time you checked out that Opti-spark?

Just because it sits under that water pump and goes bad if the water pump leaks on it does not mean it should be ignored too often.

i would change the gas filter and run a test on the fuel pump.

sounds like a bad head gasket

sound out of time ...put a light on it

ps the computer might be bad aswell

id say computer or distributor prob.