Par Car Stutter

My 2008 Columbia Par Car has an intermittent but significant stutter/clunking when the accelerator is fully released to idle. It works great as long as the accelerator is not fully released to idle to slow down but intermittently jerks and stutters when doing so, knocking out the whole system until the Fwd/Rev switch is placed in neutral and the key is cycled off and then back on awaiting the click. Is there something in that accelerator gizmo that doesn’t like to be left in the idle position for extended storage periods? The cart sat for several months this summer awaiting our return south.

Any trouble shooting thoughts would be appreciated.

My first post on this forum so be nice!

Thanking you,