I've run into a couple situations where my linkage caused similar issues. Often, I'd could give a quick blip of throttle and it woud be back to idle.

As for it rolling around, that seems to happening when you turn bigger props. They seem to make thrust at lower RPM. You can keep tuning the engine to get a lower idle. If it is still a problem, try adding some resistance to your wheels. Maybe with some toe-in as suggested or placing something like fuel tubing between the wheel and collar. Just don't get them too tight, you don't want a wheel to hang up, especially on landing.