So I have been having an ongoing problem with my 94 Vet, and it just keeps getting worse. It started by acting like it was running out of fuel and dying on me a few times and not restarting until it cooled off. It seemed to be a fuel pressure issue, but I have gone all through and even upgraded the system and have determined it is not in the fuel system. I have good fuel pressure. I replaced the ignition module for good measure. The fuel trims tell me its running lean but I cant find a vacuum leak anywhere, and all the sensors seem to be reading correctly. Since I was messing with the tune, I went back to a tune when it was running great, but that hasn't corrected it. It certainly seems to have all the symptoms a failing opti, but before replacing it, here is what is confounding me. The long term fuel trim is adding as much fuel as it possibly can, and the PCM still says its running lean. If I flash in a new tune, it clears the fuel trims, and when I start the car will barely keep running it is so lean, and immediately begins to add more fuel to the long term trims until it gets to the max trim of +25, at which point it will keep running but poorly. It misses and sputters and goes back and forth between hitting on all cylinders and not. I do not understand how a failing opti would cause the fuel system to go lean, I would think it would be sending raw fuel through and the 02 would read rich. Am I wrong about that? Any other ideas why the car would suddenly begin to run so lean on both banks not related to inadequate fuel pressure? I have had this car almost 15 years and it has never given me grief like this before, I guess eventually I had to hit the LT1 lotto. Thanks