My mom has a 2015 Equinox with the loathsome 2.4 I4 direct injection. When she showed up with it, it was throwing a P0172 rich O2 code and a P0014 over advanced exhaust cam. Apparently the car ran like poo from MI to CO and experienced intermittent run-on. It did it to me once on the drive to Advance Auto where I got some fresh 5W30. Also of note, that morning's cold start with old oil (that either barely or not at all touched the dipstick) gave a bit of a rattle up top, sounded like a VVT cam gear. After the oil change there has been no run on and zero noise from the engine anywhere. It otherwise ran perfectly both before and after the oil change. I found that the O2 sensor harness on the sensor side was laying on the CV axle and was chafed pretty badly as you may imagine. Seems odd to me it'd read rich if that were the cause though. As for the cams, I removed, inspected, cleaned, ohmed, and reinstalled both actuators for the cam phasers. They both ohmed out at 13.2 ohms and had a little bit of contaminants on the screens. I hosed them down with carb cleaner and dropped them back in. Both were dated early 2019, so they were replaced just before my mom got the car in Sept 2019. I've read that the high pressure fuel pump can develop an internal leak and flood the crank with fuel thus watering down the oil and causing cam phaser issues. This however was not the least bit overfull on oil. I decided to check and see if the low pressure side would bleed down and it looks pretty normal. I turned the key on and by the time I got back under the hood it was at 60 and falling. It seemed to park around 57, so I came back 10 minutes later and it was 52. 10 minutes later it was just a tick below 50. I left it on overnight, but feel that isn't really indicative of anything. My mom is a MI/AZ snowbird and she left the car here until kiddo #3 pops out in 10 days. I don't want to send her back with an underlying issue that's going to cost her big bucks, but I do have a few weeks to sort this out. Is there anything upstream of that low pressure schrader valve that could piss fuel into the crankcase? I imagine the odds of a leak at 2000psi are a bit higher than around 60. I should point out that she was at least 1500 miles past the change oil light coming on, so this in and of itself could be the cause. I also have to wonder if whoever did change her oil in the past skipped the PITA cartridge filter. I was too cheap to buy the special socket so I powered through it was regular stuff that barely fit in there.