OBS_Build
Newbie
Ok so since I first changed the oil on my 96 k1500 with the 5.7 my idling pressure has been at 40 pounds. When I got on the truck it was 60 pounds and that didn't change with the temperature of the engine. But now, I put 10W-40 full synthetic high mileage oil in it just like every other time, before the truck warms up the pressures are at 40 idling and 60 when I'm on the gas, however when the engine warms up, the pressure drops to 20 and idle and 40 when I hit the gas. Does anyone know what could be solving this or if its something I need to be worried about. The only check engine codes are for the catalytic converter and the EGR.