Decided to give the TDS its spring sort out as power was getting slack over 4000rpm(`s as you say). Time for spring outing to piss off Modena residents by parking outside the cavallino.I noticed that a braided small pipe from the manifold to an electonic switch was damp with diesel.It was a right tussel to get it off the manifold by the dipstick and the electonic switch due to having bloody crimp clamps on both ends. Finally did it and went out on test,difference astounding,back to pulling right to 4900 in 5th as it used to.My question for the likes of shogun is, I assume the electronics switch by the service diagnostics plug is some form of MAP(manifold atmospheric pressure) or what and is it "adjustable"??