RE: THROTTLE JUMPS AROUND
when you say it range checked good what exactly do you mean? was the engine running and did the throttle servo respond correctly?
when the throttle started surging was the transmitter close to the receiver? could be you were having some over drive issues..this is where with the transmitter close to the receiver your actually over driving another channel and it appears on the throttle channel...the fix is to walk away a few feet....