Q: Q: Idle fluctuates and then stalls.

asked by on

i have a 2011 mitsubishi lancer and it shut off while i was at a red light. i put the car in park and turned the key to turn it off, then turned it back on. it started fine and was running fine. none of the lights are on on the dashboard. what could this be?

My car has 175000 miles.
My car has an automatic transmission.

What you are describing sounds like a dirty or failing idle air control valve. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. This valve is controlled by the vehicle’s computer and will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. This is also an important function when starting the motor as it allows the motor to run and idle on it’s own once the motor fires. 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 while adjusting the air/fuel ratio constantly to allow this to happen smoothly. 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 inspect your vehicle.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Q: Idle fluctuates and then stalls.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Looking at used Mitsubishi Eclipse 2007, 100,000 miles. What is the average wear in miles on this vehicle?

Hi there. This is a very difficult question to accurately answer; as there are several variables that impact engine wear and tear such as routine service and maintenance schedule and type of driving completed. However, on the average, typically Mitsubishi...

Q: advancetrac and abs light on after cv axle replacement

This may be related to faulty wheel speed sensors which are located at each of the four wheels. These sensors monitor wheel speed which is relayed to the ABS system. When the ABS system detects an abnormal speed for the...

Q: What are these codes that appeared on my car?

These codes are related to the engine sensors for mass air flow, idle air control, and the throttle position sensor. It is quite likely, given your mileage, that their sensors have become dirty/clogged, or the sensors have failed. You don't...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.