Hi Bruce

If this is anything like the old F35 cat electrics. Then from what you have described could be a foot pedal fault. Inside the foot pedal assembly they use Opto sensors and sometimes a good clean out with a brush and some electrical cleaner can resolve the issue.

Other times it could be related to the steer sensor card which sits under the old f35 controller panel in the back which also uses opto sensors to determine the drive motor lockouts etc.