Extreme flight VANQUISH with Torque 2814/820,Flight boss 45amp speed control as comes in box.GLITCHING on 3 cell worse on 4 cell ??????????????

Isolate individual servos first to see if they are causing the problem. If not try ferrite ring on ESC lead to RX. Assuming you're using frequency radio? If you're using 2.4GHZ system still try the ferrite ring on ESC lead. Hope that helps.

Ferrite ring on as standard have changed servos no difference

All that's left that's suspect is the radio system. Run the antenna as far away from the power source as possible and see if that helps.

Have changed radio to futaba 10c 2.4 no glitching
Now using 14.8v 3000mah 25c lipo pack and APC 12*8E prop
When doing vertical knife edge loops at full power ,power keeps surging on and off ???

Good choice going with a 2.4 system. Is that an Airboss ESC or Flightboss? Never had issues with Airbosses before. Try a 12 x 6 prop. Have you checked amp draw on 12 x 8? Might be overamping ESC. Can't remember what mine was pulling ampwise but it's worth a check just to make sure. As I recall 3s=13 x 6.5 or 14 x 7, 4s=12 x 6 on the Torque setup you have. Is it surging all thru flight or at the end of the pack? Might be LVC set on soft cutoff telling you it's time for the hanger if it's towards end of pack.

now on 12*6
found esc getting to hot
put esc in cooler position