I suspected the 'infinite' control. Watched the video on your website on replacing the range burner control. This confirmed my preliminary diagnosis of the problem. I ordered a new control on Monday PM. It arrived on Thursday AM. Thursday PM we pulled the range out of its nest in the counter. It took less than 15 minutes to remove the range back plate and replace the control. It took longer for the wife to clean the range and the floor under the range and the walls, etc. while the range was out of the counter. Put the range back and the burner operates normally.
Very pleased with the service from AppliancePartsPros.