I had the same bother on my 03 auto td5. if i floored it it would cut the fuel and i would kangaroo.

I sprayed loads of the in one oil in the wastegate silver jobbie on the turbo with the skinny arm.

I then nailed it, fully throttled a few times and it went! It seems to pay to give td5s a good bit of whelly from time to time just to keep it all moving. Mine struggles if left for a week without use. I would not leave it for two weeks as I can't afford the woes it brings!

Regular use and shes a beaut!