Jfrahm

Thanks a lot for the follow-up, I would not have suspected the O2 sensor could cause an issue like that.

neilschelly

I was inspecting the wiring diagrams, and it made more sense when I looked. I can't remember exactly what it was now, but there was a shared ground between the O2 sensor heater circuit and the ECU/fuel-pump circuit. I found a plausible point where a short in the O2 sensor wiring could cause the fuel pump signal from the ECU to dump to ground, I think.

The important part is "WOOHOO!"
-N