Truck will not build air pressure pass 75 psi without pressing the accelerator. When it builds up on its own to 75psi it does it slower then normal. When I'm driving it will build up all the way to 150 psi. And it normally runs around 120 to 125 psi on the highway. The dryer is also not letting out the excess air at all. I replaced the governor dont hear any air leaks and its also holding the air pressure while idling or with the truck off. Only other thing tomention is the primary tank is going all the way to zero if I keep pressing the breaks. But secondary is still around 75 psi. Then it will come down if I keep pressing the breaks. Help me out please.