At around 2000 to 2500 RPM the engine misses. It gets worse as the temp of the car goes up. I changed the coil, I changed out the MSD box. I changed out the distributor and I put Autolites AR-25 spark plugs. I just put new Ford 9mm spark plug wires on. I don't know what else to check. Does anyone know what else I need to check or replace? Need some help. This new motor is driving me crazy.