Throttle Position Sensor
I just finished fixing my 2005 Envoy with the same problem. Your problem is most likely a dirty throttle body. If you take it to a shop they are going to want to replace it for about $500. If you clean it, you can usually fix it for less than 10. There are a couple of good videos on youtube about removing and cleaning the throttle body. Some say not to touch the butterfly inside, but you can also pull the fuses for the fuel system, or do an idle relearn procedure after you clean the throttle body so the vehicle will run properly. Basically, you can clean the throttle body with throttle body cleaner after removing the unit from the intake manifold. You will need a flat-head screw driver, a 10 mm socket with an extension to remove the vortec cover/box that covers most of the engine. There is a wire attached to the left rear corner of the box and an evap hose attached to the front left corner of the box. Then you remove the plug on the throttle body, the fuel line and four mounting bolts and the throttle body comes off. Don't use anything abrasive to clean the part--just throttle body cleaner. Also Don't drop the part. These seem to be rather delicate and using abrasives or dropping the unit will damage the coating on the inside of the throttle body. I do recommend watching the videos.
After cleaning the unit, you may need to do a throttle relearn procedure for the system to reset. look these instructions up online or call a GM dealer. You may also need to clear fault codes while driving the vehicle for the relearn procedure. It took about 20-25 minutes to remove and clean the throttle body, about 15 to reinstall it, and then 200 miles to reset the OBDII codes on the computer. My vehicle also has a faulty fuel guage wich made completing the OBD tests take longer than usual. The repair is pretty straight forward--by no means worth over $500 at a garage!!
Good luck, I hope this helps
May 09, 2014 |
2002 GMC Envoy