Chevrolet: Throttle position sensor, throttle position sensor, liter v8

Question
On a 1988 Chevy 1500 pick-up with 5.0 liter V8, does the entire throttle body need to be replaced if the sensor is bad?  I have a Haynes repair book that says "The TPS and TBI unit must be replaced as a complete unit in the event of failure."  I just don't understand why.  Thank you.
Mark Grochowski

Answer
Mark;
HI well as far as the newer year cars , I'm not that sure but if the sensor can be un-screwed than there is no reason why it can not be replaced.have you put it on a obd11 meter to see what codes pop up. if the sensor is a one piece unit than it can not be repaired but if it can come out or unscrewed there should be no reason why you can't replace it.  OK