Car is '91GT Vert. I wasn't driving it much over the winter, so I was just taking it out once a week or so. I hadn't noticed, but the battery had corroded up both posts. It had been starting, running, showing charge etc. Then one day I got ready to go, and it wouldn't start.

Checklist so far:
Checked fuel pressure, my gauge shows 38-40 measured when cranking, but fuel pump never shuts off like normal when ignition turned to run position. I usually turn the switch on, listen for the pump to come on and then shut off after pressure has built up, before I turn it on over to the start position. Has spark at plugs, I removed #1 wire and hooked up another plug, grounded it, and hit the starter and it sparked. Replaced relay under the driver's seat, no effect. Checked and replaced the starter switch in the steering column, the one that bolts to the steering column and the pin fits into to make the switch move back and forth. I'd replaced it when I first got the car, and the replacement was working its way loose anyway, so I caught it before it really failed. I'm wondering if the corrosion ate up the wires to the computer or is it really not getting up to pressure, and that's why the pump is not shutting off? Am I missing a pressure relay or sensor or something? I'm working on this thing now so Help appreciated from all the gurus!!