We tow a 40ft trailer, I have the fuel pressure set at 15psi. at HY speeds it drops to 13 not towing the trailer. don't know if that is good or should I raise it. and to what???

thanks
Mike

 

I would raise your idle pressure to 16-18 and see what it drops to on the highway. I would try to keep the pressure at a minimum of 15. That way you can keep cool fuel moving through the VP. But Bosch specs the VP for a minimum of 10 to be good, but they still fail at that pressure.