I have a gas furnace that keeps cycling then kicks out for an hour. This started since the replacement of a fan motor. Warning code is four flashes. Already jumped all sensors that could be affected by this code all was good. Took filter out, cleaned A-coil. Not sure what else to do. :confused:

Good start, now fill in the holes (brand/model # of unit, description of fault code 4).

It's a KeepRite model C8MPNO75B1ZA1 I think the code means open high temperature limit device

Or maybe it means Limit Switch Open

Was the circulating blower motor replaced? If done improperly (wrong motor, speed, rotation, or improperly installed), the unit may be overheating. How's the airflow now compared to before motor replacement?

That's all fine. Air flow is good

Why was the previous motor replaced? If it failed and the unit was overheating for a while, this "new" problem may be a "side effect" of that. Have you checked to assure the motor is wired correctly? Does the motor feel unusually hot to the touch?