2003 suburban stalls

General Discussion
1

Stalling. Took to mechanic. Replaced mass oxygen sensor. Did all tests available to him.

Then:

Start up-drive 40 miles-outside temp 90-car stalls. Turn off-wait 5 minutes-start-drive 5 minutes-stalls. Repeat 5 min rest, 5 min run, stall. All in 90-94 degree temp. Temp drops to 60 degrees in evening (in Montana where weather does that.). Car runs fine drove 60 miles, gained 2000 feet elevation. No problem.

Drove in heat next day. Repeated above. Mechanic says he is reluctant to replace fuel pump ($700.00) because he can’t guarantee it will prevent stalling.

Any suggestions?

2

@trout8

Did your mechanic conduct a fuel pressure test?

I would think the thing to do would be to hook up a fuel pressure gauge and drive the truck . . .

Did he attempt to retrieve any stored or current fault codes?

Did he hook up the scanner and make sure all the fuel trims and other pids are with normal parameters?

How much time did he spend diagnosing the truck?

If the fuel pump is to be replaced, you’d want to be pretty sure of your diagnosis

I’m leaning towards fuel pump or crank sensor, but I’m not the one working on the truck