Guide · 5 min read
The short answer
A car that shakes at idle usually has a misfire from worn spark plugs or a bad ignition coil, a vacuum leak, dirty fuel injectors, or worn motor mounts. If the check engine light flashes, stop driving. Most rough idles are fixed for $150–$450.
Rough idle causes ranked from most to least common. This guide covers Spark plugs and ignition coils; Vacuum leaks and dirty injectors; Worn motor mounts so you can describe the problem and decide what to check next.
A fault code identifies a system to investigate, not necessarily a part to replace.
Battery testing is one part of investigating starting and charging concerns.
A hands-on inspection helps connect the driver's symptoms with the vehicle's condition.
Illustrative images, not customer repair photographs.
Worn plugs and failing coils cause cylinders to misfire, creating a rhythmic shake. They're the most common cause after 80,000 miles.
Cracked vacuum hoses let in unmeasured air; clogged injectors starve cylinders of fuel. Both cause lean conditions and rough idle.
If the engine runs fine but the whole car vibrates in Drive at a stop, worn motor mounts are likely.
Spark plugs, coils, fuel injectors, and throttle body cleaning. Typical cost: $150 – $450.
Modern tune-ups explained — what's done, how often, and cost.
5 min readSteady vs. flashing, the most common causes, and when it's safe to keep driving.
7 min readSqueals, grinding, vibration, and other warnings you shouldn't ignore.
6 min readCall now for a free quote and same-day service across Texas.
