Wastegate modulator...

Yaaahhh! or so I thought when I thought that this had fixed all my problems with my TD5 auto (2002). I'd posted on here before that my Disco kept jerking everytime I put my foot down, around 2.500 revs and I tried so many different fixes but once I had it checked out on the Nanocom it turned out to be the wastegate modulator. I changed it for a new one and Bob's your uncle...well for a while anyway. It started to act up again after a couple of days although not nearly as bad. It seems that the problem has been isolated to this (not the engine loom, XYZ switch, gear oil change, etc...as mentioned before) but how does this modulator work? is it possible that it's clogged up with oil somewhere?

Cheers
Al

Have you checked to make sure the wastegate lever moves free on the Turbo ?