A friend's 95z28 383 with AI ported Trickflow heads and solid roller cam with a large duration and high .600 lift, 38lb Dephi injectors and PCMFORLESS tune has issues. Problem is at WOT the fuel pressure drops 20 psi from 48-52 to low 30's. Car has a AFPR and 255 liter pump. Changed pump and AFPR and fuel filter. Car now only drops to mid 30's at WOT. At idle and low rpms the car is pig rich and the fuel pressure bounces around from 44-52 psi but at WOT the O2's are at mid .700's to .800 millivolts (lean). The car is stong on takeoff but by the 60ft it falls on its face and will at times cutout and miss. We just put in new Iridium NGK plugs and runnig MSD 8.5 mm wires and MSD digital 6 ignition. Also the higher we set the pulse width on the injectors with Tunercat (at 19 right now) the worse it runs but the O2's are still lean. This is still on stock fuel lines. He is oviously running out fuel but why? Any ideas. We have racked our brains now we want to pick yours. Thanks
HVY SS