My father-in-law's stock XL-5 Rustler is acting pretty odd; sometimes it'll run forward/backward at full throttle on its own (throttle on the transmitter is neutral) and other times it won't respond to forward/backward input at all.
I highly doubt its interference; he said it was happening at his house (in the middle of nowhere) and then I saw it happen over the weekend while we were camping at a state park (further in the middle of nowhere).
The steering is fine. The throttle trim is set to 0. Before I saw this happen for myself I replaced the 3yr old brushed motor with a new broken-in one. I opened the receiver box and checked the for loose wires/connections but didn't see anything obvious. Unless I'm missing something obvious, that means there are only 3 possibilities left:
Before I drop it off at the hobby store and ask them to do whatever needs done I figured I'd ask you guys for ideas other than "guess and check". That can get expensive...