In my Citroen C4 Coupe which I bought sometime ago it had a Nokia hands free system fitted. When I use it everyone complains about the really bad echo. Any ideas how I can cure this.

I have a nokia in my motor, same thing I changed my phone from a sony erricson to a samsung and problem solved

I used to have nokia kits but got sick of this, I now use parrot kits which don't have the problem.