Surging symptoms are usually due to vacumn leaks or a dirty Idle Air Control valve. If the throttle biody and IAC had not been cleaned before, do it to see if it helps.
Check the coolant level in radiator as well, low coolant level would cause surging as well.
Check the coolant hoses to the IAC for clogging.
Check for other sources of vacumn leaks, brake booster, PCV.
Sunday, December 27th, 2009 AT 1:40 PM