Renault had two tries at fixing this problem, first thing does it happen at certain revs. Mine happend all the time between 2,000 - 3,000 rpm they first told me it was due to a part of the air conditioning system which they fixed. It was ok after that but the vibration returned and was then traced to my hands free kit. The cars been back a week now and no further problems, it only started after they took the whole dash off to replace the Sat Nav screen. You may have tried this already but I took the eng who was going to work on my car out for a quick drive so he could experience all the rattles.
It was Renault Croydon at Coulsdon who fixed it, dont know the name of the eng who worked on the car.
I do not take any nonsense from Renault, just because its a French car does not mean you have to put up with poor build quality. Renault have so far been very good, they accept that I have had more than my fair share of problems but they have been positive in trying to fix them.
I do not have much luck with cars my last one was a SAAB 9-3 turbo which spent 2 1/2 months solid at a number of SAAB garages over the 2 years I owned it, gave it back to SAAB with 3 major faults outstanding.
