Q: Engine idle fluctuates

asked by on December 08, 2016

Rpm fluctuating when engine is at operating temperature, the problem happend after i changed the fuil filter, spark plugs and also the radtor hoes. I changed out the map sensor a few hours ago but still having the problem.

Please help me

My car has 1800 miles. Also has an automatic transmission.

This may be a result of a dirty or failing idle air control valve. The idle air control valve reads the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. Since this valve is controlled by the vehicle’s computer, it will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed with the help of the idle air control valve making the transition from a higher RPM back down to idle speed. When the engine RPM drops below the normal range of about ~800 RPM, this often times will cause the engine to stall indicating a dirty or faulty idle air control valve. I would recommend having an expert from YourMechanic come to your location to diagnose and replace your idle air control valve.

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