Hi I have a Pro-form PF 5.2 and was running on it (at 9.1 speed) and all of a sudden the belt slows suddenly and then speeds up again, (it is really quick and happens intemittently), I have read the suggestions in the troubleshoot but these don't describe what is happening?
A treadmill will shut down/slow down/speed up from too much friction which is due to high motor current because the walkbelt and deck are not properly lubricated. Take an amperage reading from the motor and if it is above 10-12 amps steadily I would recommend lubricating the deck first and retest if it still cuts out replace the controller and finally,After replacing the controller and lubricating take an amperage reading from the motor and if it is above 10-12 amps steadily replace the walking deck because it is worn out. Apply .5 oz of lubricant on the deck every 3-6 months or 100 hours of use. This will extend your treadmill's life many years.