About 2 months back my CEL comes on to replace an O2 sensor. Replaced that. Truck still runs strange, lack of power, RPMs dropping.
Then the truck almost left me stranded because it would not start. It finally starts up and the CEL is blinking so I check that and it was for a "multiple cylinder misfire". I replace all sparkplugs and clean the throttle body. Truck runs great for a week and then it wont stay on long enough for me to get out the drive way. I replaced the fuel pump and it ran perfect for about a week again then it stalls out on me last night and the CEL starts blinking yet again. I check those codes and get that the same replaced O2 sensor is bad, the CKP sensor, and no CKP found. I just replaced the CKP last year.

Any suggestions?

I have 2005 Ram 1500 Hemi. Has just under 140,000 on it.