Mark Harper

recently purchased a 2013 Sierra, 5.3, 130k miles. Cold start - 2-3 second delay, goes to about 40psi. Warm idle drops to about 18psi. hits a max of 40psi over 2500 rpms. most cruising speeds 22-25 psi. I've checked and cleaned the sensor filter - no change. Applied 50psi of air to the pressure sensor - the gauge matched, so the sensor is good. Replaced the pickup tube o-ring, pressure was better by 3-5 psi for about a day, then back to 18-40 range. I could replace the oil pump, but I see so many posts where it may not actually help. Anyone figured out how to confirm if it's bearings vs the pump? Is the pressure range I'm running not worth worrying about?