I have a 2005 ex fleet focus 1.6 tdci and getting same issues as what you are describing. Did you get any resolve on yours. Diagnostics cam back with a few error codes so I changed the EGR Valve, Cam shaft sensor, Crank Shaft sensor, New fuel filter and still no joy. Car would start fine and go about town when engine is cold but when it is up to operating temperature, rev it past 2.5k revs, engine would splutter and die out. It does not do it when cold, only when engine is warm. It will not restart when it stalls. To get it to fire up, I have to lift the bonnet, slam it down and it will restart and continue with my journey. I am going to replace the fuel pump relay and see if that might play a part. It seem the failure is heat related and when it gets up to temperature, the contact goes further apart hence causing it to stall.