If you’ve ever turned on your car in the driveway to be met with a “rough idle” where your engine shakes, you’re probably wondering what’s going on. You’re not alone! In general, many drivers wonder what it means when your car shakes or rumbles, even at a standstill. This movement can be an indicator that several things aren’t working as they should, so pay attention if:

  • You notice your vehicle shaking when idle
  • RPMs that are inconsistent or jumping around
  • Shaking sounds
  • Skipping sounds

If you think your car has a rough idle, you probably wonder why? The truth is, there might not be one single reason, and some are far more serious than others. But, no matter the reason, one thing is for sure, a shaky car when idling is never ideal, and when combined with inconsistent RPMs, you’ll want a mechanic to take a closer look.

What Is That Shake and Stutter When I Turn My Car On?

Let’s put ourselves into a common scenario. You’ve started your car up, have it in park, or have your foot on the brake; what would your car do if everything was in working order? Ideally, it should feel consistent. There should be no skipping, stuttering, or rumbling, and you should keep at an RPM range that is normal for your vehicle. Most vehicles idle between 600 to 1000 RPMs, but some fall below. When your car is shaking and shuttering, that’s definitely a rough idle.

A car should feel smooth as it’s idle, and the RPM needle shouldn’t jump up or down drastically. A rough idle is pretty simple to detect when you first start your car, especially if you’re starting your car in colder temperatures. So keep in mind that a rough idle during your car’s cold start may be different (and happening for various reasons) from when your card rough idles when the engine is at a higher temperature.

So, take note as to when this rough idle happens. Is it happening when you turn on your car? Does it happen at any other point in time? What does it sound like? Having answers to these questions can help your mechanic have a leg up on understanding the issue.

Why Is My Car’s Idle Rough?

The great news is that a rough idle can be solved. The unfortunate news is that a long list of components, electronics, and systems can cause a rough idle. This can make diagnosing the main root of the problem tricky, but not impossible. We always recommend taking a car that has a rough idle to a mechanic before that shuttering idle worsens. Having said this, here are three common reasons why a rough idle might happen:

  • Fuel Pump – The fuel pump sends gasoline from the gas tank to the injection system. With proper maintenance, we can catch when a fuel pump begins to wear down, become clogged, or begin to fail. When a faulty fuel pump is a culprit, the engine doesn’t get enough fuel, resulting in a sputtering car.
  • Fuel Filter – Where the fuel pump sends gasoline, the filter filters out the contaminants from that gasoline. Like any filter, eventually, they’ll become clogged, slowing down the fuel flow. 
  • Fuel Injector – The entire fuel injector system plays a prominent role in starting your engine. If it’s clogged or completely gummed up, the injectors won’t be able to mix the proper amount of fuel and air, creating a rough idle and slowing acceleration.

We’ll Figure Out the Problem.

We don’t imagine every car owner will have the tools or know-how to fix rough idle issues independently. That’s why the mechanics at Master Muffler Provo are here to help! We have the decades of experience necessary to diagnose the issue and fix the root of the problem. So contact us today to set up a tune-up appointment.