This and similar problems plague these vehicles all the time. Typically, these problems are the result of the ignition module. Every time they are checked, they check fine. This is due to two things; One, they are cool when tested, just like your car is when it runs, Two, the test does not stress the electronics like your vehicle does, things like heat, vibration, and electronic drain are not duplicated; the unit then performs just fine. It is also possible, that, like everything else, the test is simplified to lights switching on and off, eliminating the dumb ass factor doing the test. If a waveform was available for the tech to observe, and he had the brains to understand what he saw, he might see what is wrong. Typically the waveform on the transistor outputs will be distorted, indicating the loss of integrity of the component. Since the module has been the culprit every time these problems occurred, I would try there. Have you tried tapping on components like the air flow meter, the cam and crank sensors, etc? If no response was observed under these circumstances, I suspect a module will repair this problem. I cannot do any testing at the time of the problem, but I would suspect that this is where the problem is. Be careful of aftermarket units at cheap prices... typically they will have the same problem as the one replaced causing you to tear your hair out. Some words to ponder. Ray