My dad bought a 2015 silverado in 2015, 4 door extended cab 1/2 ton, 4 wheel drive, Lt package, 5.3 direct injection. Great truck unil he hit 75,000 miles when the lifters failed. The dealership rebuild the whole top end of motor and ran great. I bought it off dad around 100,000 miles and after a few months it threw a code for the oil pressure solenoid was stuck open. At 120,000 miles I replaced the oil pump all the seals and truck ran great no check engine light normal oil pressure. It's at 150,000 miles now and I still drive it everyday. I use it every day of the week and there was no issues or signs of issues I was driving it this morning pulling a trailer. I then came home parked it in the driveway to unload it. Unhooked the trailer to leave again. Made it about a mile out of my driveway and it start running super rough, flashing a (orange)check engine light and oil pressure went from 40 to about 55 60psi. Came home to do some diagnostics on it have many misfire readings on my scan tool on cylinder 4. I checked spark with a inline spark tester and seemed to me a little week but not enough to really make a difference. I then switched spark plugs and nothing changed. Swaped coil packs from another cylinder and nothing changed. Tomorrow I plan to do a compression test on it but my compression tester is in my tool box at work. Has anyone delt with this before or have an idea to steer me to the right direction of what's going on. Part of me wants to say that a lifter failed again because how it acted but its not making noise like a failed lifter would make. Any help or advice would be greatly appreciated. Thank you in advance.
