About a year ago idle control became very poor on my 2007 Nissan Qashqai. When engine and/or air temperature are cold, idle falls to around 500rpm when the clutch is dipped at junctions or in traffic, then recovers to normal 800rpm.

It didn't to do this before, and it makes the car miserable to drive in traffic because the idle is too slow and the vibration is marked. Been to the dealer 4 times in the year but they either refuse to acknowledge the fault or claim it is a "characteristic of the car" - I can't accept this because it didn't do this previously.

Nissan Customer Services is next to useless and keep referring me back to dealer who say they can do nothing without a comparison vehicle. Any advice on how to proceed with Nissan or ideas of whether there is a specific component that may be failing to cause this fault much appreciated?

Totally fed up with Nissan and the car at the moment.