Dosen't happen all the time. I will run some one and the car will fall on it's face hard. All I have for fuel is 94 octane stock rails stock lines with a 255 pump and fuel regulator. Think it could be the fuel filter? The car will run in the 4,500-5,000 rpm no problem. Just the odd time it will cut out when I am on it hard. My setup is Edelbrock 2 02 heads RPM intak 70mm TB X Cam Ford Racing 42's with 80mm mass air full exhaust catted with a Novi 1220 UPR power pipe MSD BTM MSD coil and wires. The car is making 410 foot pounds of torque and 450 rear wheel horespower.Do you mean that the engine cant hit higher rpms? Like it runs strong through the lower rpms and then it wont rev past 4,500-5,000?