??Car has loss of power on both bottom and top end, it hesitates, vibrates, shudders.

My car has loss of power on both bottom and top end, it hesitates, vibrates, shudders. I think either Crank Position Sensor or Clogged Cat, car won't go over 85 MPH on my 3.4L. It doesn't accelerate fast at all and takes forever to reach 35 mph etc. Let me know. Doesn't backfire at all with no exhaust.

I did a full tune-up including: Wires, Platinum Plugs, Fuel Filter, Air Filter, Injector cleaner, oil change with flush, all fluid levels are good. The exhaust itself was busted up inside so I cut it off and the battery is brand new. Smells bad under the hood sometimes like I ran over a dead animal and won't go over 85 MPH, someone told me a clogged cat will not go over 5 MPH but I'm thinking maybe slightly clogged. CPS controls the timing and it may have bad readings from the CPS. Don't know that's why I'm here lol. I only know LT1's and LS1's.

Questioning?: CAT or COILS or Crank Position Sensor (CPS)

When I had that problem, I had a bad coil. Put on the new coil, good as new. Now I'm having it happen again, but I think it's related to the charcoal cannisiter this time, which I know is bad. The charcoal pouring out of my vacuum lines was a sure sign..:(

Smells bad under the hood sometimes like I ran over a dead animal and won't go over 85 MPH, someone told me a clogged cat will not go over 5 MPH but I'm thinking maybe slightly clogged.

Questioning?: CAT or COILS or Crank Position Sensor (CPS)
When a CAT goes out it usually smells like that

Well I don't know what it is.

My car isn't that bad, it has power and can accelerate rather quickly but when I"m idling at lights the dash shudders and shakes fro mtiem to time. Could it be my coils? I just got it tuned..