I pulled the maci fuse last night, this morning put it back in then I thought I'd check the fuel parameter on the fuel pack controller it was out 5% should have read 99% at full throttle was only 94% so I recalibrated the fuel setting and went for a test ride.
Problem solved the throttle is as smooth as silk in low gear at low speed. It was most likely a combination of the ecm and fuel pack needing calibration to the new sensor.
Didn't have any stalling issue on my ride so don't know if the fault is corrected or not time will tell and fingers crossed.
here's too all for your input.