2002 Pontiac Grand Am fluctuating rpms

2002 PONTIAC GRAND AM
70,000 MILES • 6 CYL • FWD • AUTOMATIC
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4INCHSTROKE
  • MEMBER
  • 1 POST
Rpm's flucuate between 1800 and 2000 rpms after getting up to highway speeds. Cruise control switch behind brake has been replaced, computer has been reprogramed, transmission flushed, and test driven with computer on board. The only results so far is a thinner wallet.
Feb 20, 2008 at 11:04 PM
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MERLIN2021
  • ✓Experienced Mechanic
  • 17,250 POSTS
Is the service engine soon light on? If so, have the codes read. You may 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!
Also, when was the last tune-up?
Feb 20, 2008 at 11:37 PM
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