Why does my Renault Trafic shake while idling?

Whole-vehicle vibration at idle that can be felt through the steering wheel, seat and mirrors, and becomes stronger when a gear is selected with the clutch depressed, is a typical sign of a worn engine mount on a Renault Trafic. The rubber in the mounts hardens and cracks with age, so instead of isolating the engine, it transmits vibration directly into the body. Diagnosis is simple. With the bonnet open, ask someone to raise the engine speed while the vehicle is stationary. An engine that lifts noticeably or jerks sideways indicates a damaged mount. All the mounts are usually replaced together because they work as a set and a worn mount places extra load on the others. If slight vibration remains after replacement, the next suspects are injectors causing uneven running, but begin with the mounts because they are the less expensive and more common cause.