PCM Problem in 5.9

[CaliRam2002]

Early this year, my father-in-law passed away from a sudden heart attack. I inherited his 2002 Dodge Ram 1500 2wd with the 5.9 Magnum. Prior to his passing, he was having issues with his truck of sudden stalling and crank/no start. He was never an automotive person but could repair and replace parts. He replaced the IAC, TPS, distributor cap/rotor, camshaft/crankshaft sensor and finally fuel pump/filter assembly. His problems persisted. Due to having long hours at work, never had a chance to help him diagnose the problem. Browsing the internet, he then had the fuse box (TIPM) refurbished. One day he started feeling ill and doctors found cancer. The truck sat from December 2022 to February 2023 while he battled with radiation and chemo. Then one day, he suddenly had a heart attack and we lost him. I have made it my mission to have the truck running/driving again for my wife to daily and connect with her dad. So back to the truck. After all the replacement parts, truck was doing the same. An old friend of mine told me that the PCM might be the culprit. Looking through the internet, I found Flagship 1. Ordered a rebuilt PCM from them. The first one I received, the truck would crank and start but idled horribly. It was so bad that I couldn't move the truck front or back without it stalling. According to Flagship1, their PCMs are plug and play. Sent the first one back and received a second PCM. Now the truck runs (idles horribly), runs and drives for short distances and stalls. The speedometer nor voltage gauge are working, and I now get a check engine light for a 02 sensor. I'm completely over Flagship1. Do any of you recommend somewhere else or something that could be done? I'm in the San Bernardino County in Southern California. Thanks