2001 Chevy Impala surges on start up and going up hills

Some surge problems are related to a bad or dirty IAC valve. The valve gets dirty because of a buildup of carbon and fuel deposit.

Disconnect your air intake duct from the throttle body, and with your engine idling at 1000-1500 rpm, spray some throttle cleaner into the throat of the throttle body (aim for the idle air bypass port). Don't be cheap! Give it a good cleaning and spray it real good.
Turn off your car and let it soak for a few minutes.
Turn your car back on and repeat the process.
Turn it off, and put the air duct back on there.
Turn the car back on again, and run it at 2000 rpm until there's no white smoke coming out of the tailpipe.

If it doesn't make any difference, you can remove the IAC valve from the throttle body and clean it directly that way. If it still doesn't make any difference, you either have a faulty IAC valve, or this was not the problem to begin with. :)

Is the air damp in the morning? May be a spark plug wire or a bad fuel filter. Do you have a check engine light on? When was the last time you had a tune up?