Trouble shooting F-I-L's truck

So I need some help troubleshooting my Father-In-Law's truck, with little to no information. It's a 1992 F-150 with the 5.0L engine. He reports that it stalls and cuts out while driving. He took to a dealership to get it fixed, spent about $400 and says that it is now in worse condition. The dealer told him he needed another $400-ish part, and he is guessing about $1200 in labor.

He can't remember the details, he is going through chemo to treat cancer, so I'm working with what I have here.

The mechanic at the dealership told him that it will run fine until it builds up temperature, and then it begins to run rich. That is when it begins cutting out.

I'm guessing MAP or O2 sensor? Any other thoughts?

If he finds the paperwork and tells me what the dealer did, I'll pass that along.

Thanks!

Ewwww, pre-obd2.

If it's running rich, I would suspect something like EGR and it going full flow without a cut in fuel.

coolant temp sensor was a common fail, even the way your describing it

When I saw the title I thought you were having trouble shooting the truck. I was going to suggest a shotgun.

Cutting out like 1 it quits and won't start till it cools off, or it 2 starts running crappy and eventually quits, and might restart and run crappy or might not restart, or 3 it stumbles and dies and restarts and stumbles and bucks etc?

1 implies an ignition module or something along those lines. 2 implies a temp or O2 sensor that goes badly out of range and causes it to be stupid, 3 implies the throttle position sensor has gone south.

A little time with a VOM might find the problem.

EvanB wrote: When I saw the title I thought you were having trouble shooting the truck. I was going to suggest a shotgun.

It's like we share a brain.

In reply to EvanB:

Or give it a bigger lead...

Streetwiseguy wrote: starts running crappy and eventually quits, and might restart and run crappy or might not restart... implies a temp or O2 sensor that goes badly out of range and causes it to be stupid

This...

Here is exactly what the Ford dealer did as a repair.