13-04-2015, 03:11 PM
Yeah, the ECU is calibrated for the weight of the stock flywheel - the ECU measures crank acceleration per injection event to correct for individual injectors which may not perform quite as expected and give you a perfect idle. So I'd expect it to struggle to cope with low RPM usage as it'll be attempting to compensate for the greater increase in RPMs due to the crank accelerating faster than expected and probably hunt about quite a bit.
