If its a sensor, my money would be on the TPS, but you've got a lot of choices here.
From cheapest/easiest fix to most expensive:
1. Remove Throttle Body and Clean with Brake Parts Cleaner or the like. Reinstall and retest.
2. Test Catalytic Converter with a temp gun, if it's hotter going in than coming out, the Cat's clogged and needs to be replaced.
3. Test Fuel Pump at Schrader Valve on fuel rail to make sure it's holding 46-49 PSI at all times and in all conditions.
4. Replace TPS, IAC, or both
5. Replace Crank Sensor. PITA to get to and about $80 if I remember correctly.