200tdi losing power at higher revs

This week my 200tdi Defender 90 has been losing power at higher revs (say 40mph in 3rd). The power feels like its pulsing up and down by about the same amount as when the turbo kicks in and out.

Now it is cold and damp this week, and I usually run on B100 but I've mixed in a quarter tank of DERV and it's still occuring. Oil levels needed a little topping up when I checked at the start of the week but that's the first time since September so I think I'm doing well there

Any ideas as to where I might start to look for the source of the problem?

sounds like a fueling problem... it might be something simple like a seriously clogged up filter!

chris_mack said:

sounds like a fueling problem... it might be something simple like a seriously clogged up filter!

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I was thinking that, perhaps in combination with the cold - although I did change the filter a few hundred miles after switching to B100. No harm in changing it again I guess.