Car Mechanics (UK)

Vibration on accelerati­on

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My daughter’s 2003 Nissan Cube ZB11 1.4 auto has an annoying fault that has so far stumped both me and the garage I took it to. The car exhibits a subtle but noticeable vibration on accelerati­on between 50-70mph and also when decelerati­ng. It is more apparent when taking your foot off the pedal during gentle decelerati­on. The vibration is not transmitte­d through the steering, which feels solid, but appears to be coming through the body.

At first, I thought the wheels needed balancing, so I rotated the rear and front tyres, to no avail. Then I had two new tyres fitted and had all four tyres balanced, but this had no effect. I took it to my local garage and went for a test-drive with the technician. He could not feel the vibration until I pointed it out, but had no idea what was causing it. The car was subsequent­ly MOT’D and had worn lower balljoints replaced. I have also replaced the front discs, which were badly warped. They are fine now, and I’ve ruled out brake vibration.

I am now wondering if it may be related to a degraded coil or coils causing an intermitte­nt misfire when the engine is under load. Some time ago there was a pronounced judder that was pinpointed to a duff spark plug causing a misfire. What do you think?

Phil May

Because the vibration is also present on decelerati­on, it's unlikely to be related to an engine misfire. The 2003 Nissan Cube was sold in Japan, so I'm assuming your daughter’s vehicle was imported. The automatic gearbox used was a constantly variable transmissi­on (CVT) and it’s possible that this is the source of the vibration. I would check the gearbox fluid and ensure that it is up to the recommende­d level and doesn't have a burnt smell or brown colour; if it does, this would confirm a problem with the gearbox.

I would also check the driveshaft constant velocity joints to ensure they are well greased and have no signs of wear. Feel for any excess play by tugging on the driveshaft and attempting to rotate the shafts back and forth while checking for any movement. If you haven't had the steering geometry checked since the lower balljoints were replaced, I would get this done first.

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