I've got a 2008 Hybrid Yukon with 190,000 miles on her. She's recently started to have oil pressure issues on the gauge dropping below 40 at idle, and RPM drops below 1000 with a rough idle. I changed the oil pressure sensor behind the motor in 2015 but didn't know about the screen (didn't change it). The oil pressure is hit or miss. Sometimes the motor runs great all day, always going to Autostop at red lights and low speeds, and other times the oil pressure is always at or below 40 on the gauge. I did an oil change 500 miles ago with 5W-30. I'm stumped on what it could be. Plugs are relatively new and clean. Oil pump going bad? I've seen others pull the pan. I've also seen someone post about a 2nd sensor on the side of the oil pan. The rough idle and not going to hybrid is eating me alive!! Any thoughts?