Benjamin Negron

Ok so a cold start it diesels before it starts cold idling the pressures a lil above 40 as It drives to normal op temp it drops to about 10-15 is this normal and should I be alarmed?

Injuneer

At idle, that pressure would be acceptable. GM actually accepts idle pressure as low as 6psi before it turns on the "check gauges" light. Probably indicates a bit of engine wear, but it's not a problem. Assumes you are running the correct grade oil, and it isn't overdue for a change. What is pressure on a warm engine at 2,000 RPM.... at 4,000 RPM?

Not sure what you mean by "a cold start it diesels before it starts"??? Dieseling means the engine runs with the key off on compression ignition, no spark ignition.