No Power 2001 Ford f150 4.6 vehicle

I have a 2001 Ford f150 4.6 L. I am having trouble figuring out what Is wrong with it. It has no power and it shakes bad when acceleration and decelerating. If I'm on highway and doing 40 as soon as I hit gas rpm will go all the way up to 3500 or so then it will like catch and rpms will drop back to normal but engine bogs out. Can't get it to go 55 unless I'm on a down slope. Codes come up 171. I checked for vaccum leaks, cleanef maf sensor, changed air filter, new o2 sensor. My exhaust is rattling soon as let off gas pedal. Shakes bad. Help me please.

My guess is a clogged catalytic converter.