2004 Chevy Trailblazer erratic throttle

2004 CHEVROLET TRAILBLAZER
140,000 MILES • 6 CYL • 4WD • AUTOMATIC
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GEORGE7369
  • MEMBER
  • 1 POST
my truck is having problems when idiling and under load it lobes up and down
Jan 6, 2008 at 12:26 PM
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MERLIN2021
  • ✓Experienced Mechanic
  • 17,250 POSTS
It sounds like you have a vacuum leak, get a can of spray gumout, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs!
If no leak found, check egr system...
Jan 6, 2008 at 6:29 PM
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