I have a 97 ram 1500 5.2 and it seems to run absolutely terrible for a few seconds after started in the morning. It sounds like it has a wild cam. I've replaced the pcm and 3 upstream o2s as well , could it be a bad cat? I do hear some rattle play at the cat. I can't figure it out. It smells horrible of gas at the tailpipe as well

 

O2 sensors play no role at all on a cold start. When is the last time the truck had a tune up? How is fuel pressure? Have a scanner you can plug in, and read live data? Would be interesting to see what the PCM thinks coolant temp, and intake air temp are at cold start.