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Q: Car had a hunting idle so replaced Iac valve and now it idles at 2200 rpm's cold and 1000 rpm's warmed up.

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I had a light hunting idle so I adjusted the biss screw and it didn't change so I then bought a new Iac valve and replaced it. Battery was unhooked for 24 hours because I had to replace the clutch kit and I replaced the Iac valve at the same time. I checked cam and crank timing and it is exact. I checked for vacuum and boost leaks and found none. I even reinstalled the old Iac valve but no change. I am stumped as to what this could be. Do I need to drive with the new Iac valve for a certain amount of time? Any suggestion at this point would be greatly appreciated.

My car has 126346 miles.
My car has a manual transmission.

A: Hello. You car does have an adaptive memory...

Hello. You car does have an adaptive memory when it comes to the idle control valve. Over time the computer is going to adjust the placement of the valve to compensate for water and carbon build up. In some cases, driving the vehicle around 100 miles straight will cause changes. But more importantly, going through 20 or more key cycles will cause the idle control valve to adapt.

The best way to resolve this would be to use a factory scan tool that will allow you to go into the computer and clear this adaptive memory back to factory. If you are looking to have this done, consider using YourMechanic, as a certified mechanic can come to your home or office to inspect and repair your high engine idle speed problem.

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