I have a 86 mustang gt very modified. Engine has rebuilt bottom end, Canfield aluminum heads,custome grind blower cam, 1.70 howards roller rockers, 30lb injectors, 255lph fuel pump, edelbrock performer intake 70 mm throttle body, 75mm pro-m mass air calib. For 30's vortech -v1 supercharger with smallest pulley about 12lbs of boost crx racing intercooler w/3" piping. Ok the car ran awesome with stock blower pulley making about 5-6lbs no cooler, but I can't leave well enough alone. Went to 12lb pulley and intercooler. Bumped fuel pressure up to about 55 lbs to give a better shot of fuel. Car pulls hard till 5000 rpm then sputters and coughs immediately I let off don't want to hurt her. Any ideas it may need bigger injector but what size? Mind you this is a street car never sees track time. I don't want it undriveable. Idle fluctuates too didn't do this before. Please advise.... Thanks