I installed an older sidewinder esc and 5700 kv motor in my ultima db and im having a problem with it. When you stab the throttle the buggy takes off a few feet then stops then gets going again and stops until finally it gets going full speed. this only happens when u mash the throttle all the way. If you slowly ease into the throttle its gets up to speed like it should. Any ideas?

Set the timing low and the punch control high, together or singly, and experiment with those settings. Check your solder connections and motor wire/esc connections. One connector may be bad.

It sure sounds like a wire/connection issue. Like its not able to supply enough juice at full acceleration. just curious, does it do it when not under load (like hold the car off the ground and try it)?

or try it with no punch control. I had an issue with one of those a while back. It would screetch and stutter with ANY punch control dialed in. 0 punch control and it was fine. It now sits on the shelf collecting dust!