Area51

Sounds like a bad door lock actuator.

I had a similar issue with the starting and replaced thr battery...it was better, but not fixed. I've also replaced the ECT sensor at least once. On vacation, I had to replace the ECT sensor and thermostat again, and all they had in stock was the "premium" AC Delco brand. Popped it in, and the truck starts fine now, and idles a bit higher when cool like it should.