Q: I have a hunting/high idle.

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The idle sits at about 2000 rpms with the tps unplugged. If i plug it in the idle will surge from 1k to 2k constantly. The issue is only while in neutral, as far as i know i do not have any vacuum leaks. Unplugging the iacv causes the idle to drop to about 1500, i believe the iacv is in working condition. The map sensor has been changed twice but it could be bad, i do not know how to test that. I have tried a lot of little things to fix the idle as its my daily vehicle and i cant dive into something unless i know itll fix it. Any help would be appreciated

My car has 212000 miles.
My car has a manual transmission.

Hello. An irregular idle can be caused by many things. If the idle speed appears to stabilize with the throttle position sensor then it may be possible that the throttle position sensor is the source of the issue. The MAP sensor is another possibility, though unlikely if it has already been replaced twice. A voltage or resistance test would be able to determine if the component is functioning correctly. A few other things to look at would be fuel system, ignition system, and the engine management systems. An issue with one or more of the components to any of these systems, such as a fuel pump, injectors, or vital engine sensor, may result in an unstable idle due to the fact that the computer receives its commands for idle speed from the engine management system. It may also be possible that the idle air control valve itself is the source of the issue. If you are unsure, I would recommend having a professional technician, such as one from YourMechanic, come to your location to diagnose what may be causing your irregular idle.

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