93 yukon stalls.
Im helping a buddy with his yukon. He bought it with a direct port injection setup on it. Harness was all chopped up, so he fixed the harness, put the original style. Throttle body setup on it, and now it stalls when put in gear and dies . What I think the issue is that the direct port injection setup requires 40 to 50 fuel psi,and the tbi only needs like 10 to 13 psi. But I can't find a inline fuel pump, could they have put a high flow intake sending unit.
I would do an actual fuel pressure test before the filter and see what the pressure is at. Since it sounds like you actually have to little pressure to run the motor. Then go from there.