Back to all

Idle Talk about Engines (Causes of Rough Engine Idling)

January 24, 2021

When you slow down at stoplight, your vehicle's idle should be smooth as silk.  But what happens when the engine is missing or idling roughly? That's your engine's way of telling you, "Hey, I've got something wrong with me and if you don't get someone to find out what it is, I may not start the next time you turn the key."

You can help your service facility if you can describe the problem in detail.  Here's a list of things to make a note of:

  • When is the problem happening, when the engine is cold or when it's been running for a while?
  • Does the rough idling occur when I'm accelerating or when I'm going at a steady speed?
  • Does it happen at high speeds?  Does it happen low speeds? Does it happen at both?

Make sure you describe the problem in as much detail because it will help a technician diagnose the problem.

One of the first things they'll check is how the spark plugs are firing.  Modern iridium plugs are supposed to last a long, long time.  But they CAN eventually wear out.  Inspecting the firing end can help the technician figure out the root of the problem.  Corroded or worn out spark plug wires, too, can contribute to an idling irregularity. 

There are other potential problem spots, too.  The technician may check the ignition coil, timing piston rings, valves and cylinder walls. 

If the mixture of air and fuel isn't correct, that may affect how smooth your vehicle is running.  Your service facility is equipped with diagnostic equipment that helps them pinpoint the problem.  Once that idle is smoothed out to the way it used to be, you'll be the smoothest operator on the road.

Tuffy Joliet (South Plainfield)
2031 SR 59
Joliet, Illinois 60586
815-436-1829

More articles from Tuffy Joliet

Why did my vehicle fail its emissions test?

November 30, 2025

We all want to breathe clean air and keep our planet green. One of the ways to do that is by requiring all vehicles with internal combustion engines to pass an emissions test. Thats because these vehicles can be big polluters. Everyone wants their car to pass the test so they can continue the... More

Oil Times are a-Changin' (Oil Change Synthetic)

November 23, 2025

When it comes to oil changes, things are really changing. Most newer vehicles require synthetic oil, and while it costs more than conventional oil, it doesn't need to be changed as often. When conventional oil was the only game in town, you changed your oil every 3,000 miles/5,000 km. But as tec... More

If the Shoe Fits (Brake Shoe Replacement [Rear])

November 16, 2025

When it comes to brakes on your vehicle, we all know how important it is to keep them working well because they are vital safety equipment. After all, if you cant slow down and stop, you cant drive safely. While many vehicles use what are called disc brakes, theres another type of brakes that ... More