I put a Race tune off here on my buddies 01 LB7 and he has been running it for about 3 months now with no problems. Well today the truck started running bad, I checked for DTCs and a code P0463( his fuel sender has been doing this since he bought it months ago). Only way I can describe the way its running is, it ran exactly like my old 04 LLY did when they stock Relief valve in the fuel rail went out.. I put the PPE Race valve in my LLY and that fixed the problem. Can I do this with a LB7? His the truck trys to rev and go but it won't its really sluggish reving.. Any ideas??? He just had all 8 injectors replaced about 6,000 miles ago. I loaded several tunes and even his Stock tune back up and it still does it. Just simply feels like the motor is cut back BIG TIME on fuel and is limping.. But no codes??

possibly a bad maf, try maxing out the maf tables and see if that helps. but more then likely just a dirty fuel filter...

You need to use Scan Tool to gather more info.

Ive spoke with him already and told him to scan some things once he had some time and see whats going on...:)

The fuel filter ended up back off some and was sucking air.

Good to hear you guys got it fixed!

Good to hear you guys got it fixed!
It was a easy fix but tricky too hah