Hello and thank you ahead of time for the help. As the title says I have a 2021 Ram 1500 with the 5.7L. The truck has about 110k on it and has been entirely problem free until now. It’s throwing a P0301 code fairly regularly, and sometimes it even causes it to run rough. It has also very randomly thrown the P0305.
Let me start with what I’ve done to diagnose it. I’ve put new plugs in, moved coil packs, moved injectors, and I’ve done a compression test. The misfires stay in cylinders 1 and 5 (cylinder 1 especially) and the compression test returned equal pressures in all cylinders.
I religiously change the oil and have only used high quality synthetic oil and Wix filters since the truck was new. I examine my oil for metal after changes and have never found flakes or glitter. This is leading me to believe that the lifters and cam aren’t the cause, especially because the engine runs quietly. Next I thought maybe the MDS system was malfunctioning but cylinder 5 isn’t deactivated during MDS. It’s possible that these two cylinders have dropped valve seats but this is supposed to be an issue on 08 and earlier hemis, not +09 hemis. A cracked head is also not out of the question entirely, although I do not have any issues with losing coolant or oil, and no cross contamination of either. The last cause I can think of is electrical (injector or coil signal wiring, or maybe ecm). Without buying new harnesses I can’t rule that out.
I would love to delete the MDS with the Melling kit but I live in CA and from what I can tell I won’t pass smog with it. Do you guys have any other ideas? Have any of you had issues like this with a fix?
Let me start with what I’ve done to diagnose it. I’ve put new plugs in, moved coil packs, moved injectors, and I’ve done a compression test. The misfires stay in cylinders 1 and 5 (cylinder 1 especially) and the compression test returned equal pressures in all cylinders.
I religiously change the oil and have only used high quality synthetic oil and Wix filters since the truck was new. I examine my oil for metal after changes and have never found flakes or glitter. This is leading me to believe that the lifters and cam aren’t the cause, especially because the engine runs quietly. Next I thought maybe the MDS system was malfunctioning but cylinder 5 isn’t deactivated during MDS. It’s possible that these two cylinders have dropped valve seats but this is supposed to be an issue on 08 and earlier hemis, not +09 hemis. A cracked head is also not out of the question entirely, although I do not have any issues with losing coolant or oil, and no cross contamination of either. The last cause I can think of is electrical (injector or coil signal wiring, or maybe ecm). Without buying new harnesses I can’t rule that out.
I would love to delete the MDS with the Melling kit but I live in CA and from what I can tell I won’t pass smog with it. Do you guys have any other ideas? Have any of you had issues like this with a fix?
