poor torque MK2.5 Di

[allegroequipe]

I'd welcome thoughts on this as it's got me stumped....
My tourneo has 135k on the clock and doesn't use oil. Will do 84mph on the flat but feels stiffled and slows on a decent hill.
She's done 50k on biodiesel but started to slow on my last batch, am now on third full tank of diesel and no change.
I've changed the torque sleeve though it looked good.
Done the leak off mod, new fuel filter (twice) and lift pump.
I did the egr valve, cable tied intake and fitted pipercross filter plus injection pump pressure mod (1.25 turns) when I got her and she's never missed a beat.
The torque sleeve and piston where clean as a whistle, no shiny bits indicating wear and the throttle pin moves ok - lifts the plunger all the way up.
With the pressure at 2.5 turns, power is back from halfway up the rev range (like a weak turbo kicking in).
Loath to change injectors yet, no rattles from tappets. New cam belt too (timing spot on), no difference.
Cracked injectors open, no air locks and fuel cap breaths ok.
So, unless the piston spring has stiffened up I'm stumped!!!

[Kedishen]

New fuel filter
New air filter

and

Chuck in some injector cleaner

[FredTransit]

Er Mk2?

Check the lift pump. If you have one. You say biodiesel. Is this processed veg oil or just veg oil? If the latter, like I said check your lift pump isn't blocked.

[allegroequipe]

Oops, meant MK5 2.5.
Bio was home made, converted from waste veg oil. Good quality, ran ex wife's D4-D on it and cured sticky turbo with it.
Bus has had two new fuel filters, injector cleaner, oil flush and filter, air filter cleaned and re-oiled too! Even ran it with air filter and no difference.
Fuel filter is full when I take it off.

[robbie.cee]

Red 2stroke oil... bang a half liter in and run her good... cheap fix if its all just gunked up