Why is the engine idle dropping and raising ?

1998 VOLVO V70
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DCMEZA
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After changing the timing belt the cars surges high and low and now sometimes stalls when the idle drops too low
Jul 13, 2012 at 3:53 PM
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WRENCHTECH
  • ✓ASE Certified Mechanic
  • 20,761 POSTS
  • ASE Certified Mechanic
First eliminate all vacuum or air leaks in the system. You may have a bad IAC ( idle air control) but try cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.
Jul 13, 2012 at 4:08 PM
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