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: How do I change a tire if I have a flat?

Spend enough time driving and it’s going to happen – you’re going to get a flat tire. It happens to all of us eventually. Knowing what to do will make the process less stressful and frustrating. Here’s what you should...

Q: 1999 camry shifting hard?

Good clean fluid is important, but the problem with most automatic transmissions is that the fluid that you change in the pan is only about a third of the fluid in the transmission. Many shops use special equipment to flush...

Q: Car stopped after rough idle

This is a common symptom of a faulty idle air control module. This module regulates the control of air being mixed with fuel at idle. When this is faulty, it will cause an imbalanced amount of air and fuel to...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...