Lunch Box problem

Hello, need some advice. My stock Lunch Box was running fine but after I ran it in the park up and down the hill a few times, it began to jerk - power, no power, power lag, then it works fine the next day, but it just happened again. If I pull the trigger slowly it works fine but then a harder pull the motor would start jerking. The front wheel servo works fine so don't suspect it is a reception problem, would it be the ESC? I tried switching it to a different remote, but same problem. IS this a common problem? It would be a happy problem if it is the stock motor as I am thinking of replacing it with 'black skin pig' or a 25T anyways(sorry can't type Chinese)

THX

If  you are using 原裝電變, this happen when there is not enough battery, try to charge the battery, and i think it won't happen again!

ESC could be over heat. Try to change better ESC.

Bros, thank you for your advice. I did try to swap it with a fully charged battery but the problem did not go away. I do suspect it is somekind of overheating problem as it seemed to run fine after it is cool. I also have a TB-02 Stock Subaru Impreza, wonder if I can swicth the ESC to test it out as both are using the same 'white pig skin' motor.

In case I need a new ESC, how much is an acceptable replacement(like to keep the budget low).

THX again!

MC230 $2xx, MC330 $3xx, V16R $200

Rcrounder. wow the ESC is half the price of the LB, I may as well buy a new Gold version or buy a new stock ESC, hopfully it is cheaper. THX anyways!