I know for a fact LT's opti's go out pretty quick if I recall correctly, so the fact the dealer said that is no surprise.

 

i think i have the same problem, my car runs fine for a minute then, as soon as i give it some gas it want bogg and an occasional pop when i gas it, i have a 94 z28,

 

This is from the OBDII.com people. Hope it helps
RANDOM MISFIRE CODE
A random misfire means your engine is misfiring, but that the problem is not isolated to one of two cylinders. It is jumping around in a random way from one cylinder to another.

A random misfire code usually means the air/fuel mixture is running lean. But the cause might be anything from a hard-to-find vacuum leak to dirty fuel injectors, low fuel pressure, a weak ignition coil, bad ignition control module, bad plug wires or compression problems. Even a dirty MAF sensor can cause a lean code and/or misfire to occur.

The first thing to check is the intake vacuum with a vacuum gage. On most vehicles a normal reading is 17 to 21 inches Hg. If the needle is lower, is jumping up and down or steadily dropping, you have a vacuum problem. Look for possible vacuum leaks by checking vacuum hose connections, the throttle body and manifold, and PVC valve and plumbing. An EGR valve that is leaking can also act like a vacuum leak and cause a random misfire.

The next thing you should check is the fuel pressure with a gage. If it is not within specifications (refer to a service manual for specifics because fuel pressure is critical for proper engine performance), the problem may be a weak fuel pump, low voltage to the pump (check the relay and wiring), or obstructions in the fuel line (like a plugged filter). A bad fuel pressure relay can also leak pressure and prevent an otherwise good fuel pump from delivering full pressure to the injectors. Dirty injectors can also restrict fuel delivery and cause a lean fuel condition. Many regular grades of gasoline do not contain adequate levels of detergent to keep the injectors clean. Frequent short trip driving accelerates the buildup of injector deposits. Cleaning the injectors with a good quality fuel tank additive (or having them professionally cleaned) can solve this

 

hey try looking at the fuel pump my 96 z28 did the same thing i spent almost a grand trying to fix it until it died on me and then i could hear the fuel pump wasnt running so i would listen to it to see if it sounds right