Alternator failed now replaced.... now more problems arise!!

Actually, the throttle position sensor has nothing to do with idle speed. It simply tells the Engine Computer the speed and direction of throttle movement. Both of the symptoms you described are commonly caused by a vacuum leak. That will cause an increase in engine speed without a corresponding increase in power, and a lean condition burns too quickly and can result in a knock. I'd look for a loose or cracked vacuum hose first.