Power / Throttle problem on 2008 Peugeot Boxer 3L

Hi I seem to have a problem that even Peugeot can't fix, so any help would be appreciated.  The emission control system warning light came on a few weeks ago when on holiday.  A local Peugeot dealer ran the diagnostics but found nothing so did a reset and everything seemed ok.  Then last week it came on again and this time was accompanied by a loss of power and particulary poor acceleration.  My local Peugeot dealer came up with the need for a new Throttle Body but on fitting it the problem was still the same. They have had the vehicle nearly a week now and seem no nearer finding the solution.  Has anyone else had a similar probelm?