I have a 2012 Chrysler 300 SRT 8, 70,000 miles. About a year ago the CEL came on. Codes were for bank 2 position 1 and bank 2 position 2 O2 sensor. Replaced upstream sensor first. 6 weeks, or 2 months later CEL came back on. Bank 2 position 2 O2 sensor. Replaced downstream sensor. Problem fixed until about a month ago. CEL came back on. Intermittent misfire cylinder #8 . Replaced ignition coil and sparkplugs. Engine started missing. Took to a new dealer (mine closed) who I didn't know anything about. Said it had wiped a cam because one of the roller lifters had locked up. They've had the car three weeks and said it might be another three weeks, lifters are on back order. After researching this, it seems lifters are a common problem with these engines, especially the 5.7's, not so much on the 6.4's. (Maybe because the 6.4 is a rarer engine? If I had to guess the lifters are the same part number.) My question is this, could the O2 sensor problem a year ago have been a warning that this was happening, since both problems are on the same side of the engine? The car is covered under powertrain warranty, but am I going to have this problem again in another 60,000 - 80,000 miles. I'm planning on keeping this car. What recourse do I have, if any ,with Chrysler because of this. Seems like they know this is a problem. Any thoughts or comments would be appreciated.