Is that stall rpm?
Is it better when cold?
Is it worse with more throttle?
if yes times 3, then check your firing order, and separate numbers 5 and 7 wires. If those are ok, then disconnect the Vcan and roadtest again. If still bad, check the Power-timing beginning at whatever rpm it starts . Make sure TDC of the piston is TDC on the balancer.
Pre-Ignition going to detonation, can feel like that. Detonation must be Eliminated.
