2003 Silverado 1500HD 6.0

[Ryaneh11]

Hey guys my truck runs perfect unless it's under a load. I travel a lot for fishing and the truck has a lot of hesitation when I haul my boat. I got my fuel pressure checked and it reads 52 psi. Range being 55-62. I changed the fuel filter and still the same 52 so I changed my fuel pump today and it still reads 52psi. I just replaced plugs and wires as well. I've checked for vacuum leaks and didn't find anything and cleaned the MAF sensor today too. Any thoughts guys much needed

[Ryaneh11]

I forgot to mention when it does hesitate it throws cel and 4-6 lean O2 codes

[txab]

Did you check the fuel pressure regulator?

[rjgti]

injectors maybe

[mjoekingz28]

Try higher octane fuel.

[Ryaneh11]

Yeah I checked the fuel pressure regulator no gas coming out of the vacuum line and when I pull the vacuum line off the pressure jumps up but when I put in on it'll jump back down. As far as injectors go, if one was stuck open the pressure would leak down pretty quick and it'll stay 50-52 for a good 10 minutes anyway

[Ryaneh11]

I just changed the fuel pressure regulator and still 52. I've checked it with 3 different gauges too