Back to all

Idle Talk about Engines (Causes of Rough Engine Idling)

November 17, 2019

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.

Auto Lab Troy
2790 West Maple Rd.
Troy, Michigan 48084
(248) 643-7690

Need Service?

Request a Quote

More articles from Auto Lab Troy

Cabin Air Filter and Engine Air Filter: What?s the Difference?

March 8, 2026

You may have heard someone say they just got the air filter replaced in their vehicle. But did you know your vehicle has two different major air filters and they both perform quite differentbut very importantduties? Todays vehicles have a cabin air filter, and an engine air filter. The engine a... More

Why is My Brake Pedal Hard to Push?

March 1, 2026

When you push on your brake pedal, you should find your vehicle easy to stop. But at some point, you might notice stopping takes much more pressure on the pedal than it used to. When it gets to that point it becomes a safety issue, and you should bring your vehicle in so we can track down whats... More

Power Steering Pump Replacement

February 22, 2026

When youre driving and you hear a squeal or groan when you turn, it may be a sign your power steering pump is on its last legs. The same is true if you feel your steering is slipping or doesnt respond to your hands like it used to. Precise, responsive steering is, of course, important when it ... More