Well... FML! The cat wasn't the only problem. I can tell car can breath better but more than half throttle is still killing the car. I'm getting a p0300 (Random Misfire) code and the car definitely feels like it but only at 50% or more throttle.

Maybe I cracked a plug, got a bad set of wires, not sure what else.. Anyone have any suggestions on where to start looking now? Btw, I've already done a tune up with plugs and wires, did the lim, plenum, and throttle body gaskets. I did pour half a bottle of seafoam in the tank when the cat got clogged but the cars been sitting with the same gas for almost a month. Could the gas have gone bad that quick? Its depressing putting all that work into it to be far worse than when I started.