I have a 2007 Silverado 2500 classic with the 6.0. A year and a half ago it started cutting out when accelerating and sometimes would give me a bank 1and 2 running lean code. But not always. I replaced the spark plugs and seemed to have fixed the problem but then started doing the same thing again. It continued to get worse. Only seems to do it when it’s hot outside. The truck runs at normal temps. But when it’s a hot day 80+ it acts like it’s running out of gas all of the sudden. I can pull over and let the truck sit for 15-20 mins and starts right up and drives 4-5 miles before starting to act like it’s running out of gas again. Dose not always do this but just randomly will do it. So far I have cleaned the throttle body, new mass air flow sensor, and new catalytic converters, but just the other day while headed out on a trip started to do it again. When it dose do this it just kinda chugs along and if you try to give it more gas it cuts out more. Every time I take it in to have it looked at it runs fine and they tell me everything looks great and is runnning as it should! Please help me! I’m lost

 

I had a similar issue with my 2004 Suburban 2500. It woul lose power and nearly stall on hot days when I went above 6000 ft (e.g. going from beach level to mountains). It was the fuel pump module.

I tried testing everything easy and resisted replacing the fuel pump for years but that's what it was.

It could have been the pressure regulator or the actual fuel pump but I don't know if you can buy a pressure regulator sepately (aftermarket fuel pumps are available as a separate part).

I think it was a vapor lock that the fuel pump could not overcome or the regulator would not permit a high enough pressure to overcome.