Rough Idle

When your car shakes, vibrates, or sounds uneven at idle, the engine isn't firing smoothly on all cylinders.

Rough idle means the engine is running unevenly — you'll feel vibrations through the steering wheel or seat, hear the engine stumbling, or see the tachometer bouncing. The most common causes are worn spark plugs, dirty fuel injectors, vacuum leaks, or a misfire on one or more cylinders. A rough idle that gets worse over time usually points to components that are gradually wearing out rather than a sudden failure.

Start with the basics: spark plugs that are worn or fouled can't ignite fuel consistently, causing misfires and roughness. Dirty fuel injectors spray fuel unevenly, leading to an imbalanced air-fuel mixture across cylinders. Vacuum leaks let extra air in, leaning out the mixture. A compression test can reveal deeper issues like worn piston rings or a leaking head gasket if the simpler causes are ruled out.

A rough idle is your engine asking for maintenance. Ez Mobile Mechanic handles these diagnostics at your location — we're a mobile mechanic in Jacksonville who comes to your home, office, or wherever your car is parked. No tow truck, no shop drop-off. We serve all of Northeast Florida. Call (904) 788-7272 to get your idle smoothed out.