98 Concorde cuts off!!!

I own a 98 Crystler Concorde LXI 3.2. I've noticed a foul smell comming from the exhaust as I back up ( as if I back up into the smell ). Also, the RPM starts to drop, the car will shake, and sometimes will just cut off completly. I have also been in a drive thru and had the car cut off from what seemed like a lack of acceleration. It has it's problems while in drive yet idle. Please help me understand what is going on with my car. I also just added more oil which is now at a normal level. Without this car, I cannot go to school like I am now... PLEASE HELP!!!

Jen - VA:banghead: