I have a 2003 Monte Carlo LS and today it started acting funky. Within the last week i replaced the thermostat and water pump in an effort to fix the over heat but that problem remains unfixed. I am getting circulation through the upper hose but not to the lower, and today it started smelling like burning rubber when i was cruising at low rpms.. Along with this smell the rpms are bouncing between 400-850 at idle, i have to push the gas nearly to floor to make it downshift and accelerate.. after about 5 seconds of me holding the gas pedal it takes off as if there was no problem at all.

Any advice? Ideas? Anything? I just need my car running like normal as this is my daily driver and i would like to get things fixed as fast as i am able to.

Thank you in advance to anyone that posts on this matter and tries to help me out.
-Alex