brushless problems

i hav a worrior 12020 and an bk xl8 :026: :026: :013: :013: :035: :035:
i have just put new esc in and pulled awheels off and put the truck up on blocks programed perfect . i started giving the truck abit of throttle and was running good i ran it for about 2 minets at half throttle then at full throttle then i notice than it was serging i stoped truck and checked every thing even the whole drive train every thing was smooth .so i then started again 3/4 throttle was ok but again full throttle was still serging so i tryed programing again . ran good un till i hit full throttle then i seen a little bit of white smoke followed by a pop the esc had done the same as the other one . i found this very strange how the truck was off the ground the motor was a bit hot but not to bad . do you think the motor mite be faullty and is causeing the esc to go . truck has not even run over five minets .i put my twin motors in with no problem . i will send esc and motor back . can you please have a look at them . i have checked every thing possible but there is nothing i can see that would cause this