I tried to narrow it down, although I didn't have an oscilloscope to hook up. I couldn't get it to stumble or die idling or driving normally, but if I rev the engine up to 4,000 RPM it would start to cut out like a rev limiter. But I don't think the PCM will rev limit at 4,000 RPM even in neutral. I put it in first gear and floored it and would get cutouts that were sharply on-and-off, not at all like a fuel pump getting weak which in my experience is more like running into a pillow as engine power falls off. Also I had my son sit in the back with his ear to the pump. There wasn't an audible indication the fuel pump was having trouble.
So I do think the CKP (service manual term) is a likely candidate. Service manual also shows it is a PITA to replace, requiring one pull and re-install the harmonic balancer. And if one pulls it, it should probably be replaced with a new unit as the rubber often fails with age. And belts. Maybe the tensioner too. Guess I should change the water pump while I'm in there . . .
I'm thinking I should be absolutely sure it is the crank position sensor first, given the work and expense involved. I was thinking of bringing an oscilloscope home from work and probing the 3X and 18X signals while revving the engine to 4K. I don't suppose there is an easier way to confirm the failure.
