Ok, Ive been having an issue with my 2000 Jimmy 4x4 stalling when it is hot (85*F or hotter) outside. Jimmy has about 130k on it, newer fuel pump. It will stall, i get low fuel pressure and have to wait 10-15 min before it will start up again. It will happen on these hot days after driving for about 40 miles or 40 minutes, whichever comes first.

I have read through several posts regarding this topic but i have not seen anybody reply with a solution to the problem.

I have obtained a fuel pressure gage and worked through the diagnosis sticky (at least most of it anyways) when the truck is cold. Keep in mind there is no issue whatsoever when the truck is cold. Everything checks out OK, fuel pump and fpr seem ok from the diagnosis sticky.

When it is HOT and it dies the pressure does not go over 45psi. It is consistently in the 40's everytime this issue arises. I cant go through the whole diagnosis when this happens because it dies when i am on the road (usually in the middle of an intersection!) and i only have about 15min before it the pressure will go back up to an acceptable level and it will run fine.

On cool days i have no issues whatsoever and i can drive the thing for hundreds of miles without an issue. It runs excellent, starts right up the first time and has plenty of power.

I am completely stumped, I just dont understand how 10 or 20 degrees ambient temperature can make such a big difference?? I dont want to just start throwing money and time at this replacing things that arent going to fix the problem.

The stalling is an inconvenience but I am more worried about possibly causing damage to the motor by running it lean when the fuel pressure is low.

ps my fuel pump is about 1.5yr old with maybe 20k miles on it. Fuel filter was changed about 6 months ago and is still clean. Pump is a Carter brand...

If anybody has had and fixed a similar problem I would greatly appreciate your input here!! thanks.

 

I would lean towards the pump being the cause. If you were to get things ready to connect the fuel pressure gauge to the fuel filter line, eliminating the engine side of the fuel system, do you get the same low fuel pressure results?