ORIGINAL: Redcat Support
have you dropped your transmitter? And (this was on an electric, but radios are radios) I have seen a steering servo make the throttle act goofy. I don't know why it happened, but as soon as the steering servo was replaced, everything was fine.
I would replace BOTH servos and see if that solves your problem.
At any rate...if you've replaced all that stuff, and still haven't replaced the steering servo...steering srevos are NOT hard to replace, so why not replace it just to SEE if it works?