Q: Rough idle and flickering lights.

asked by on

What is causing my car to run rough while in idle and my lights are flickering. Any suggestions? It is a 5 speed with quite a bit of miles.

This may be related to 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. This valve is controlled by the vehicle’s computer which 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. The lower idle may also cause the lights to dim in the event that the battery may be weak. As the RPM’s dip, the production of the alternator dos as well, causing the charging amperage to the battery to drop. I would recommend having an expert from YourMechanic come to your location to diagnose and repair your idle air control valve.

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. Rough idle and flickering lights.

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: Rattling noise on the front, right side.

There are a few things that may cause this type of noise. A loose panel like a splash guard or exhaust heat shield may rattle as the vehicle moves. The sway bar end links are another common spot for rattles....

Q: Q: Car shuts off while driving

Hello. Most of the time if the car just shuts right off then it is caused by a main relay that is failing or a distributor issue. I usually start by determining if the engine is losing spark or fuel...

Q: Cold idle problem with my car, looking for software update.

Software updates are fairly common today with modern vehicles. They can correct issues that the manufacturer did not foresee in testing. In general, programing does not take a lot of time. I would say that half an hour should be...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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...