I just finished up a McLeod RST clutch, flywheel and Ben Calimer stage 1 transmission install . While I was there I installed an MRT 3" mid pipe and a Ford Performance aluminium 1 piece driveshaft. Upon driving the car, a 2012 Boss, it ran fantastic. I then had it in 5th gear and stepped on the throttle, it did not like it, it ran terrible, the check engine light was flashing, the car was vibrating, once I got some RPM on it everything went back to normal, acts like I am lugging the motor. Any ideas?