My Impala just started, putting, stalling, it hesitates and has low power when you push the gas, but then power comes back, when you stop it putts, and when you stop and get out of the car it stinks, a bad odor, I dont see any leaks and it just started this last night, please help?
First, is your " Check Engine" light illuminated? If so, then that is the first thing you need to check. You can take your vehicle to AutoZone, or any other major parts store and ask them to hook your computer to their scanner. It's free. Once you get the trouble codes, ask them for the definitions. That will point you in the right direction.
From the symptoms you describe, it sounds as if you have an exhaust restriction. Probably the catalytic converter.
To be sure, I'd need to know exactly what your " Bad odor" is. If it smells like a rotten egg, or dead rat, then your catalytic converter has gotten clogged up.
But replacing it won't solve your problem. You need to find out why you converter got clogged up and fix it, or your new one will get clogged up as well.
Most of the time, your engine is misfiring and dumping raw fuel into the exhaust. This melts down the inside of your converter and clogs it up. You need to find out why your engine is misfiring.