Bought this car 3 weeks ago (wish i'd stayed with VW's) when i take my foot off the gas when driving i get a loud knocking sound if i push the clutch in it stops. So c.v joint i thought but it's now doing it when sat still if i rev it to 2000rpm i get the noise, seems if i turn the wheel hard left it gets louder.
If i'm driving and get the noise it stops when i turn right.
It sounds like a vibrating knocking sound.

 

And when starting from cold i get a massive cloud of smoke and it runs very lumpy

 

Smoke and lumpy running sounds like injectors and also sounds like your dual mass flywheel is on its way out !!

Both VERY common faults on Mondeo's !

 

If you bought it from a dealer, take it straight back. If you bought it privately then you've been sold a duff one by the sounds of it.

 

Surley if dual mass it would be louder when you push the clutch in??? and why would it change when you turn the steering wheel?