What would cause my oil pressure to go up 10psi by letting off the gas? /forums/images/graemlins/confused.gif It happens at highway speed when the engine is under load and I let my foot completely off the gas. It goes from 20 to 30 psi. Average cruising pressure is 25psi, and idle is 5psi. This is a mechanical gauge, and I even checked it with 2 others. Any ideas?