8 common mistakes to avoid when selling your car
The 8 most common mistakes when selling your car privately in Australia — from overpricing to the Notice of Disposal most sellers forget to lodge.
Why does my car shake when I'm stopped at the lights?
It's one of those things you notice and immediately start second-guessing. The car is shaking at idle, not dramatically, but enough that you can feel it through the seat or the steering wheel. Maybe it happens every time you stop, or maybe it's more noticeable in the morning. The fact that it stops when you start moving again makes it easy to dismiss. Don't. A car that shakes when idling is telling you something specific, and it's usually one of four things. Some are a straightforward service item. One is a reason to book urgently.
Spark plugs: the most common culprit
Worn or fouled spark plugs are the single most frequent cause of shaking at idle, and they are worth ruling out first. Spark plugs ignite the air-fuel mixture in each cylinder. When a plug is worn, deposits-coated, or simply past its service life, the ignition becomes inconsistent: some cylinders fire cleanly, others misfire. A misfiring cylinder produces uneven power strokes, which creates a rough, shaky idle.
The first sign is often a check engine light alongside the vibration. In a four-cylinder engine, one misfiring cylinder means 25% of the engine's combustion events are wrong, which produces a noticeable and rhythmic shake rather than a random shudder. A used Honda Civic with an overdue plug change is a common presentation, as the four-cylinder petrol engine makes misfire symptoms very clear through the idle.
Spark plug replacement is a routine service item. If you're unsure what a standard car service covers and whether plugs are included, that guide covers what actually gets checked and what doesn't.
Engine mounts: the gradual one
Engine mounts are rubber-filled brackets that hold the engine in place and absorb its vibration before it can reach the cabin. A healthy engine produces constant vibration, but you don't feel it, because the mounts are doing their job. When the rubber degrades or a mount breaks, that vibration transfers directly into the chassis and everything attached to it.
