2004 Dodge Ram 5.7 liter Hemi

Removing the cat's isn't usually a good idea, first cause it's not legal, but mostly cause the ECM needs to be reprogrammed to compensate for the lack of back pressure. Before the advent of computer controlled fuel injection, you could cut out most of the exhaust just so the engine could breathe, leaving out what it'd do to the exhaust valves. But today the ECM is designed/programmed to an exacting standard...including...the cat's and their effect on the exhaust. If you change this in any way, it's messes up the fuel trims, both long and short. So now you have, more than likely, what ever your problem was AND the added problem of the ECM running your Hemi extra rich to compensate for the absent cat's.

Afterthought, the cat doing it's job properly, will react to the exhaust in such a way as to effect the O2 ratio to other gases in the exhaust stream, the downstream O2 now sees this problem in spades. The purpose of the downstream O2 is as a cat monitor, you removed it. There are countless articles online about how to "fool" the O2 sensor into thinking the cat is still there. It involves installing spark plug anti foul adapters. I'm thinking that if you install 1 or more of these mod's, it "might" help the O2 sensor problem and restore some semblance of normal fuel trim to the ECM. Good luck!