Do you mean a throttle position sensor?
It's hard to tell without actually seeing the vehicle, but you need air, fuel and spark for an engine to run. If any of these are not working properly the vehicle may stall.
You need to have the vehicle diagnosed by an ASE certified shop or dealership to see what is actually happening.
〉 Answered on Apr 20th, 2007 by Lori Johnson, Owner and Instructor at Ladies Start Your Engines