Interesting tidbit.

Buddies truck that I built for him. Full delete/H11 studded. Powermax turbo. RCD 205cc sticks. Airdogg 165. SCT.... yada yada yada.

IMPORTANT PART:
New injectors + Air Dogg

Sticks had been in for 3 months or so. Truck was running "Funny" for 2 days before he got it to me. Still smoked like a freight train but was boggy kinda like gelling up or plugged filter. Start looking into it. Air Dogg making NOT A SOUND! Check fuses - good. Power down - good. Confused

Unplugged the pump completely. IT STARTS AND RUNS!!!!!!!!!! Warranty pump. All better.

so FYI it is completely possible to run a 6.0 with negative fuel pressure! Still waiting for the sticks to go out because of it but was a total HOLY **** moment.