shadow460
Full Access Members
Sorry for the long post, short story is the throttle jams when it's almost closed and I need to know if I should coat the throttle body with something after I clean it out.
About a year ago, I had problems with my throttle sticking open just far enough to cause the engine to race when I park the truck. There was no check engine light. I took the advice of the members here and cleaned out the throttle body. That time I just used a rag. Before I cleaned out the throttle body, the throttle would return to somewhere between 19.2% and 21% according to my Actron scan tool. After cleaning it would snap back to 18% every single time.
The truck ran great until recently. It began trying to race in park, then one day the RPM shot up to around 2200. That evening I cleaned out the throttle body again with some B-12 Chemtool and another rag. I hooked up the scan tool and saw that before cleaning it was returning to 19.2%. After cleaning, the best I could get was 18.4. The truck ran OK and the throttle was consistently going back to 18.4% or 18.8% so I stopped worrying about it.
This evening it raced again, this time up to 3100 RPM. Like always, I tapped the gas pedal a time or two and it slowed down. It slowed to about 1200 RPM then slowed completely before I could dig the scan tool out. Throttle position was 18.8% when I got the tool hooked up.
I can't figure out what gives here. The throttle body is squeaky clean. I cleaned it out again and I cleaned out the idle air valve, oiled the throttle cable, and put it all back together. I'm still getting random values between 18.0 and 18.8 with the throttle closed. If I hit the gas and bring it to 18.8% open that way, the engine does speed up, but it won't always speed up when my foot is off the gas even if the scan tool says the throttle is at 18.8%.
Fuel trim levels are usually between -3% and +5%, with an occasional spike to +12% and then right back down. Most of the time they're right around zero. The scan tool reports that the check engine light should not be lit, and it's not. The throttle position seems to change smoothly on the scan tool as I press and release the pedal.
I am starting to think the throttle sensor is jamming up when it gets close to closed.
Any ideas? Also, am I supposed to re coat the inside of the throttle body with anything after I clean it?
About a year ago, I had problems with my throttle sticking open just far enough to cause the engine to race when I park the truck. There was no check engine light. I took the advice of the members here and cleaned out the throttle body. That time I just used a rag. Before I cleaned out the throttle body, the throttle would return to somewhere between 19.2% and 21% according to my Actron scan tool. After cleaning it would snap back to 18% every single time.
The truck ran great until recently. It began trying to race in park, then one day the RPM shot up to around 2200. That evening I cleaned out the throttle body again with some B-12 Chemtool and another rag. I hooked up the scan tool and saw that before cleaning it was returning to 19.2%. After cleaning, the best I could get was 18.4. The truck ran OK and the throttle was consistently going back to 18.4% or 18.8% so I stopped worrying about it.
This evening it raced again, this time up to 3100 RPM. Like always, I tapped the gas pedal a time or two and it slowed down. It slowed to about 1200 RPM then slowed completely before I could dig the scan tool out. Throttle position was 18.8% when I got the tool hooked up.
I can't figure out what gives here. The throttle body is squeaky clean. I cleaned it out again and I cleaned out the idle air valve, oiled the throttle cable, and put it all back together. I'm still getting random values between 18.0 and 18.8 with the throttle closed. If I hit the gas and bring it to 18.8% open that way, the engine does speed up, but it won't always speed up when my foot is off the gas even if the scan tool says the throttle is at 18.8%.
Fuel trim levels are usually between -3% and +5%, with an occasional spike to +12% and then right back down. Most of the time they're right around zero. The scan tool reports that the check engine light should not be lit, and it's not. The throttle position seems to change smoothly on the scan tool as I press and release the pedal.
I am starting to think the throttle sensor is jamming up when it gets close to closed.
Any ideas? Also, am I supposed to re coat the inside of the throttle body with anything after I clean it?
