I have a 91 with a Powerdyne Supercharger and a Edelbrock 80 HP Nitrous Kit. The car has been DynoTuned to 418 RWHP without NOS with a chip. It was running Great until i didnt start it for about 4 months due to body work on her. The Optima battery was fully charged when i started it but it hangs up at 4000 RPM. I have a Walbro 255 LPH fuel pump along with a MSD 46 GPH external boost a pump. The car idles at 38-39PSI but drops to 32-34 at WOT! I changed the MSD & filter but still have the same problem!! Any Ideas?