Suzuki 4x4 Club™

[vendy15]

(I have posted this in another area as was not sure where to put it?)
GV tdi 2004 with the hrw engine wont drive over 40mph but I can still use full revs?
I had a problem with frozen water in fuel filter which has been replaced now.
( by the way which is a pig of a job!)
Starts up first time every time and is ticking over ok.
no engine warning lights or other fault lights!
No miss fireing

anyone who might know what has happened?

Regards

[Google]