What are the signs that a throttle body is starting to fail?

Throttle bodys will make your car use more gas if it is starting to get carbon build up on it. This can be fixed by cleaning it out you do not need to replace the throttle body. Just take off the intake tube from it and look inside and turn the throttle so it will go horizontal in the chamber and look to see if it is black and dirty. If it is then go to any car parts store and buy a bottle of air intake cleaner and just spray it in the throttle body while the car is running and give it some gas so you can clean off the back side of the plate.