2002 GMC envoy stop engine and low oil pressure light I changed the oil pressure switch and tested the oil pressure, oil pressure is 12psi at idle after 20 min and jumps to 65psi at 3000rpm. The lights come on at idle after 20min of driving.
The oil filter by-pass valve is in the engine, not in the oil filter.
That’s what I would suspect is wrong.
12 psi is the low limit for the switch. As you probably know, the trailvoys don’t have a real oil pressure sender. They have a switch that indicates min 12 psi. The gauge is run by computer algorithm using projected pressure based on rpm.
New switch? Then oil is toast, or engine getting worn out. If engine oil is fresh, try high mileage oil or higher viscosity to see if idle pressure comes up. If it does, you probably have worn out bearings. How many miles on it?