Why Is My Engine Idling Rough or Misfiring? Causes and Fixes for Redding Drivers
Bring Back a Smooth, Steady Engine
A misfire means one or more cylinders isn't firing properly. Left alone, it wastes fuel and can damage the catalytic converter. We find out which cylinder and why.
A slight shake at idle: book this week. A flashing check engine light, heavy shaking, or lost power: stop driving and call us.
Why is my engine idling rough or misfiring? Usually because one cylinder isn't firing properly, most often from worn spark plugs or a failing ignition coil. Clogged fuel injectors, a vacuum leak, a dirty airflow sensor, or low compression can cause it too.
A rough idle feels like shaking or shuddering when you're stopped. A misfire feels like a stumble or hesitation, especially when you accelerate, and often comes with a check engine light. A flashing check engine light means the misfire is severe.
Common causes of a rough idle or misfire
- Worn spark plugs or a failing ignition coil. The most common cause. Tune-up service
- Clogged fuel injectors or a weak fuel pump. The cylinder isn't getting enough fuel. Fuel system service
- A vacuum leak. Cracked hoses let in unmeasured air.
- A dirty air filter or airflow sensor. Engine air filter replacement
- Carbon buildup or low compression. More common on higher-mileage and direct-injection engines. Engine diagnostics
Engine shaking at stoplights?
Book an engine diagnosis before a misfire damages the catalytic converter.
How we find the cause and fix it
- We read the misfire codes to see which cylinder is affected.
- We test that cylinder's plug, coil, and injector, and swap parts to confirm the cause.
- If needed, we run a compression or leak-down test to rule out engine wear.
- You get an estimate before we repair anything, and we confirm the misfire is gone with a road test.
Get your smooth idle back.
Book a misfire diagnosis and tune-up with an estimate before any work.
Is it safe to keep driving?
A mild rough idle can wait a few days. A flashing check engine light, heavy shaking, or loss of power means stop driving: unburned fuel can overheat and destroy the catalytic converter, which is an expensive part. See also check engine light is on.
Services we offer that could fix your problem
We confirm the cause first, then recommend only the repair you need.
- Tune UpBring Back the Power and Efficiency Your Engine LostLearn more
- Engine DiagnosticsGet a Clear Answer About What's Wrong With Your EngineLearn more
- Fuel System ServiceFix Hesitation and Poor Mileage Caused by Clogged Fuel PartsLearn more
- Engine Filter ReplacementLet Your Engine Breathe Easy and Run More EfficientlyLearn more
Common questions
Why Is My Engine Idling Rough or Misfiring?
Usually because one cylinder isn't firing properly, most often from worn spark plugs or a failing ignition coil. Clogged fuel injectors, a vacuum leak, a dirty airflow sensor, or low compression can cause it too.
What causes an engine to misfire?
Usually worn spark plugs or a failing ignition coil. Fuel delivery problems, vacuum leaks, and low compression are other causes.
Can I drive with a misfire?
For a mild misfire, a short distance. If the check engine light is flashing or the car shakes badly, stop driving; it can damage the catalytic converter.
Will a tune-up fix a rough idle?
Often, when the cause is worn plugs or a dirty air filter. We test first so you don't pay for parts that won't fix it.