I have a truck that I bought a while back with some preexisting problems. 02 2500HD LB7
The main problem is the thing can't get out of its own way. When stone cold, it barely responds to throttle input, barely comes off idle even when floored. As it warms up it gets better, but acts like it is limited to 1/4 throttle or less other than trans shifts late or kicks down on heavy throttle input.
It starts easily when cold and runs smooth with no unusual noises. No CEL ever.
No smoke and 11 psi is the most boost I have ever seen.
Almost tolerable it I load level 4 tune, but only with heavy input.
My bone stock LB7 3500 flatbed running on 7cyl has way more power. It has a valve train problem.. :-(
I have Torque Pro for logging, but it has its limits. Can't afford EFI Live yet.

New Fuel filter (Dealer tested for restriction in fuel system @ 2hg)
Tested Rail Pressure and it scales properly and Demand / Actual stay close.
Injector Balance is within spec. (Injector Age unknown) Not Making Oil!
PO did head studs 30k ago and Truck has 210k on it. (Said He couldn't afford to do the injectors then.
Checked engine harness connectors and 1 pin was pushed in a little, but no change.
Cleaned MAF and swapped with other truck, No change.
MAP Seems to scale fine ( Maybe I should swap with known good?) Cleaned, no help.
New Batteries and have tried another pair.
Currently set to stock and ECM was updated at dealer recently with no change in power.
The only think tech said was MAF not scaling to 450? I was able to get there but it took a while. Cleaned / Replaced made no difference.
Had an AFE intake on it, switched to stock and noticed a slight change, but not much.
Changed Trans Filter and topped off ATF as I heard that could affect it.
Exhaust is a 4" MBRP SS Catback system so no restriction there.
Not California model so no EGR.

I am at a loss why it refuses to give it fuel, like something is holding it back. Anyone nearby have EFI Live or a tech 2? I can only do basic checking and logging with Torque Pro and I can't afford to go back to the dealer or throw parts at it. I have spent many a night researching and testing only to come up empty handed so far. Maybe if I get a chance I will recheck or swap out MAP and even the AP? Sensor. I believe they both show the same with key on.

Any help solving this would be greatly appreciated...