Of course uphill the engine is under load. I guess it could be a multitude of things given how many sensors cruise control takes an input from. Best thing is to get a scan done and see what transpires from that first. Best to clear the codes having noted them down, then go for a run ( with cruise on!) and re-read the codes.ob1coby said:Mostly going up hill, when I have the car in cuise, it is pulsing. on off on off. Anyone ever had this? Causes?