car lost power after replacing cat and o2 sensors

Did you do this work or did you hire a mechanic ? Either way you need a new mechanic , sounds like a minor repair turned into an incompetence nightmare

I had the codes ran and did the work myself, except the changing of the catalytic system, seems like every since I replaced that everything else had went down hill from there... I was about to go get a new timing chain and water pump and do that next. But I really don't want to keep dumping parts on the car if it's not going to fix it. But at least I know what's new on it at this rate.

When the code came up I did the small stuff first, I got the egr valve, the dpf sensor, tps sensor, idle air control, and replaced hoses. The light never went off so I took the car down to the exhaust shop and the said the ceramic carbon in the cat was crushed causing it to do that, so I bought the new cat and had it installed, he called later and said just so you know your manifolds are cracked also, so when I picked up the car I did the manifolds myself he was right when I unbolted them the one on the driver side came off in pieces. Then the o2 sensor lights came on taking about the fuel ratio being to lean, replaced that and my check engine light went off, too it to get it to pass inspection did great, go to leave inspection station and the car didn't want to go, the rpm are reading high so I looked and seen one of my wires to the spark plugs had got hot and melted so I said screw it let's just replace them all. Ran fine when it starts but put it in gear and the rpm still wants to go like it has no power.