motor cuttting

[filmoor]

Having trouble with the motor cutting out started doing it after a bump but now seems to be more often when the motor cuts I still have steering. so I dont think it is a lipo cut issue as this would shut down the bec and stop every thing? all conection look good from esc to motor etc Setup is Xray T2 2009, ESC Losi excelorin, motor speed passion v3 13.5t, rx/tx acoms 2.4ghz technisport and using orion carbon 4600 lipo. I think its an esc issue. Any ideas or other thing to check please.