on code p0121 were is the switch a located at? 2007 silverado

Question

were the switch a located at and will this cause the truck from running at times and die?

Answer 1

P0121 Throttle position TP sensor 1 performance

Yes this will cause the vehicle to run and sometime stall out, The throttle body opening affects the performance of the MAP (manifold absolute pressure) where it goes outside a calibrated range, this code are more than likley cause by the TPS,which is part of the throttle body,The replacement of the throllte body will be necessary, and make this a hobby in replacing.