RPM's go up but no acceleration

I've been having issues with the thermostat on a 2003 v6 Malibu. The thermostat issues may or may not be related to my current problem.

I'm driving on the interstate and the temp jumps from 1/3 to overheating in 30 seconds. I think the thermostat is going nuts because it's been doing that lately. All of the sudden I hit the gas, get higher RPM's but no acceleration. The car will move slowly on it's own in drive but I can hit the gas as hard as I want, hear the engine rev, but get no acceleration. Any ideas?

Sounds like a plugged cat....

Sounds like a plugged cat....

What does one do to unplug the catalytic converter? Can't I just remove the thing all together?

The thermostat may be sticking. that or theres air in the cooling system

EDIT: Also unrelated to the acceleration issue