Back to all

Idle Talk about Engines (Causes of Rough Engine Idling)

January 26, 2022

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 Tire & Auto Service Glendale Heights
1153 Bloomingdale Rd.
Glendale Heights, Illinois 60139
630-588-8846

More articles from Tuffy Glendale Heights

Snake in the Engine (Serpentine Belt)

January 4, 2026

There's a belt that snakes through your engine. It's even named for a snake, the serpentine belt. It'll bite you when it breaks, possibly leaving you stranded. So, it's good to know a little about this snake-like belt. In early engines, there were lots of belts. They were used to convert the r... More

Mileage Headed Downhill? (What Causes Bad Fuel Economy?)

December 28, 2025

Name someone you know who enjoys spending a lot of money on gasoline. Yeah, me neither. Thats because it costs quite a bit to keep fueling your vehicle. One way to save money on gas is to get good fuel economy, and most of todays vehicles are designed to maximize your mileage. But you might f... More

In the Red (Why a Vehicle Overheats)

December 21, 2025

Heat is one thing that can damage a vehicle, especially if a problem isnt taken care of soon. Be on the lookout for signs that its getting too hot in some parts of your vehicle, starting with the most obvious one: the heat gauge/warning light on your instrument panel. When you see that heat gaug... More