1996 GMC Sierra IDLE PROBLEMS

1996 GMC SIERRA
150,000 MILES • V8 • 4WD • AUTOMATIC
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DANDCCONNELL
  • MEMBER
  • 1 POST
MY ENGINE CONSTANTLY IDLES BACK AND FORTH HIGH AND LOW. WHEN I START IT, IT STARTS UP HIGH FOR ABOUT 30 SECONDS BEFORE DROPPING DOWN WHERE IT SHOULD BE. IT RUNS FINE WHEN I'M MOVING BUT WHEN I'M AT A STANDSTILL IT IDLES UP AND DOWN WHILE SITTING THERE.
Mar 1, 2008 at 5:29 PM
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MASTERTECHTIM
  • ✓ASE Certified Mechanic
  • 4,750 POSTS
  • ASE Certified Mechanic
does vehicle have ac? is it possible ac compressor is making engine surge?
Mar 1, 2008 at 5:42 PM
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