04 F350, 114k miles. Truck has a hard start/no start condition. Mechanical oil pressure gauge is installed in the low pressure system, and when the truck finally starts it builds about 25psi at cold idle. Which quickly drops to 15psi as the truck warms up, and will soon be at 0-5 psi when the truck warms up more. Can a leak in the HPO system be large enough to create a low oil pressure condition in the LPO system? Or should I be looking in the LPO system first? Thanks.