lately I have needed to keep my foot on the pedal sometimes for 10+ minutes until the idle speed becomes automatic, if I lift my foot off the pedal too earliy the rpm just slowly drops off until the engine quits and I re-start.
Your help would be appreciated - before I go and buy a new alternator, belt, battery etc.

Optional Information: 2000 Ford 4x4 expedition
Already Tried:
adding water to the battery