just to update, I think we found the source of the problem. I didn't get a chance to take it out until sunday, but it ran for about 2 hours then cut off again, and we had it towed home.
I had a leaking radiator overflow hose, which I knew about. The car wasn't overheating at all, and it had plenty of coolant (it was only leaking the excess), but I've been so strapped for time lately I hadn't gotten a chance to get a replacement hose. well, we unscrewed the overflow resevoier just about a 1/4-1/2 turn, to release the pressure so it'd stop leaking until we could get a hose, and decided I'd just keep a watchful eye on the heat until then. well it never overheated, but I think we decided that the computer must've sensed the pressure loss and whenever it went to "reach" for more coolant, it shut itself down.
we replaced the hose and it seems to run alright again, except the towtruck drive jacked up my e-brake unnecessarily hard, then proceeded to pull the car up the flatbed even with the e-brake on, and now the brake handle is limp. I think the cable just came off, but it's just one more thing keeping me from driving the tour

it sucks cause I'm stuck in my mom's PT cruiser

I'm going to look at the e-brake cables today, it better be easily fixed or that mofo's payin for damages. stupid tow truck driver...