a very odd problem indeed!

im assuming that it came with a standard radio, and not the 2.4ghz radio.
if so, is the antenna in the controller screwed all the way in?(it came not in the remote right?)

have you tried it outside? i know there is one spot in my house, where ALL my radios glitch really bad but they work fine otherwise.

also, try disconnecting the steering servo from the reciever(channel #1) and see if it drives without glitching. sometimes, if a steering servo is bad, it will still move but mess with the controls. its rare, but i have had it happen to me.

oh, to test range outside, or with the steering servo disconnected, place the truck on a box so the wheels dont touch the ground and walk away while seeing if you still have throttle control.

i hope its something simple. the vortex is a great little truck!