You are turning the radio on first, then turning the car on second, correct?

AM systems is subject to glitching and run aways due to interference unfortunately. If you're running it around overhead high voltage lines, find another place to run it. I had the same probs in my backyard with a Tmaxx and its AM radio. I solved my probs by converting to FM (before 2.4ghx came out).

You can add a failsafe - this is a device that stops the RC in the event of low battery voltage, low radio battery voltage, no radio signal, and signal interference. This is the one I used until I charged to FM (failsafe builtinto the radio) -

http://www3.towerhobbies.com/cgi-bin...P?I=LXEYG2&P=8


Ideally, upgrading to a 2.4Ghz radio system would eliminate any interference and prob have a built in failsafe.