Help Ck-7w Problems

[Jayman220]

Hi all have a question which desperatley needs help please ! Ive had an Experia Z for a while now great phone with only 1 problem thats really annoyed me for a long time ! I have a Nokia CK-7W hands free kit in my car and since ive had this phone its intermittently cut in and out during conversations ! I assumed the car kit was at fault but recently bought a new control box to replace the old one and have found the new one does exactly the same ! I can only conclude that the phone is at fault as its the only sensible answer ! Ive had several Experia phones with this car kit an Experia X10 mini pro which did the same thing and also an Arc S which did not. I have the latest software update on my phone ans so im quite baffled as to what to do ?? Has anyone else had this problem ? I can only explain the problem as some kind of lag for about 20 seconds at a time cut in and out making my conversation and the conversation im listening to sound like a robot it does it at random ! Thanks to anyone who can advise !!