'knocking' On Deceleration.

[Daveyboy20]

As title really - when backing off the throttle there is a disconcerting noise from what seems to be the front right but could be underneath me, it's hard to tell. It's a knocking noise as if hitting the floor with a metal bar. For example, back of the throttle approaching your motorway exit and it'll do it for between 1-3 seconds. Does it at slower speeds if the revs are taken high, in say 2nd and then backed off but not as consistently. I've had the whole front end apart fitting new springs and shocks and I can't for the life of me find anything it could be! Nothing is loose etc..

[mantasrme]

Does the gear lever move when the knocking noise is heard? If so look at engine/gearbox mounts allowing the engine to move and maybe exhaust hitting floor.

Normally its the ns mount that allows the engine to lift that side when under drive and drop when coasting.

Can be made to move when stationary, handbrake on and engine running then let clutch up to biting point with bonnet up to see if engine lifts.

Also check for movement in front wishbone bushes.

Hard to see when prying against the bush itself

But with handbrake on and car on ground use a longbar and socket on a wheel nut and over tighten to see if wheel moves forward then loosen to look for travel backwards.

[lamchop77]

Could it be the exhaust knocking on the bodywork under your feet, and that might be caused by the gearbox mount being goosed!!??

[Daveyboy20]

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Edited April 22, 2014 by Daveyboy20

[Daveyboy20]

Thanks guys, it could well be that thinking about it - the gear stock doesn't move when it's knocking though. The gearbox mount does appear to be worn too - is it a nasty job?

[cam.in.head]

check that the exhaust front pipe isnt too near the swan neck mounting bolt for the subframe brace