i have a fuel delivery or supply issue. not sure which, we have ran this 2000 chevy express van with a 4.3l vortec, on carb cleaner briefly and it has 60 psi fuel pressure, no codes present, other than m.a.f. sensor out of range, due to cleaner intrusion. after scanning and pinpointing tests, maf shows to be fine and circuits are also. i am stumped !! i am not a novice.