Problem with car stopping for no apparent reason

[supah]

I need some help figuring out why my Lazer zx-5 sometimes just stops up.

Suddenly its acting really weird, never been like this before - been running perfectly for a long time, then suddenly it has started to stop every now and then. Nothing happens when I squeeze the speed trigger, it just stands there. If I wait for a few seconds it will run again, but then stop not long after. Steering works while it stops, but throttle not responding at all.

Anyone got any ideas of what might be wrong?

The motor was a bit hot but I had no problems holding my fingers on it. The battery was not hot at all, nor was the ESC. It ran without any sort of problem last time, but today it was acting all up after I had been driving it for like 10ish minutes. Runs perfect, stops up, runs again, stops ect. As if it "cuts off".

Only thing I had changed from last time I drove it was a setting on the ESC, changing it from "4-7 cell Nimh racing mode", to "Lipo/Nimh automatic mode". So I was thinking maybe it cuts off Nimh batteries as well, and not just Lipos, with this setting? I changed it back to 4-7 cell Nimh racing mode, but the problem still occured.


This is my setup:
LRP 5.5T Brushless
LRP Sphere Comp. 2007 ed. ESC
3600 and 4200 Nimh batteries used while having problems.
Spektrum DX2 radio, Spektrum SR3000 reciever.