2002 Buick Lesabre throttle body

Tiny
RONALD SMITH
  • MEMBER
  • 2002 BUICK LESABRE
  • 3.8L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 200,000 MILES
In the past few months I have periodically experienced unintended acceleration while driving along at rural road speeds. I have goosed the pedal and that has stopped it. However this past week the symptoms have become more pronounced. The car starts well and runs well with the fast idle kicking off normally. However, when I go to accelerate the car will maintain that speed reached and will not die off by removing my foot from the accelerator. And in fact the car will often continue to accelerate itself and reach perhaps 60mph. I have shifted to neutral and the rpms have fallen off, but not every time. The rpms have reached 4-5000 in neural and I have shut it off. This becomes more pronounced as the engine gets hotter. The throttle springs and mechanism seem to move freely when cold and pop back easily to idle position, but they are stiff when hot and reluctant to move back to idle. A local shop cleaned the air breather system and lubricated the throttle springs and mechanism but it has not helped. Some suggestion has been made to me that the throttle body needs a thorough cleaning. The linkage to the accelerator peddle seems sound and not binding. Any suggestions as to what to have checked out?
Friday, March 21st, 2014 AT 5:01 PM

3 Replies

Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Let me look and see what type of throttle body you have. Have you checked for vacuum leaks yet?
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Friday, March 21st, 2014 AT 7:10 PM
Tiny
RONALD SMITH
  • MEMBER
  • 2 POSTS
No, I have not checked for air leaks. Whats the procedure to do so? I have sent along a couple of picks to show the throttle body on the 2002 Buick.
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Saturday, March 22nd, 2014 AT 2:12 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
The best way to check for leaks is by injecting smoke into the intake and look for escaping smoke. Also at idle you can spray carb cleaner around the intake gasket around the vacuum lines looking for the engine to stumble die or increase in rpm. Its better to spray around carb spray and watch on the scan tool for the fuel trim to spike. It looks like just a throttle cable system not throttle by wire. Do you ever have a high idle?Also have you checked for codes yet?
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Saturday, March 22nd, 2014 AT 11:15 PM

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