golf poor power!

[vw754]

115 BHP PD GOLF TDI 2001.

It will go upto 80mph,then start to drop speed,if i try to go over 80,it will do it but it will take a while.

If i drive it and im in say...3rd gear and i slow down and put it in 2nd gear, if i put my foot down it wont go,slow as a slug!

Also get a vibration underneath the front of the car.

new maff fitted and no fault codes via vag-com

 

[Caesium]

Any hoses off? Changed the fuel filter recently? Does it rev up out of gear?

 

[vw754]

no pipes off,new filters,revs full when on idle.

 

[Teutonic_Tamer]

The ends of the fabric-braided vacuum hoses often cause problems on these when they crack.

Check each end for degridation (carefully pull them off, and inspect the inner bore), and if necessary, cut half an inch from the end of any suspect hoses, re-atach, and see how you get on.

 

[vw754]

PD 115 bhp,very sluggish car,timing checked using proper lock tools,been on vag-com and snap on fault diagnostic equipment,also been to dales diesel injection specialist..no faults except one( n75 boost valve positive deviation) replaced the n75,still comes up with same fault,but only after driven for a few hours.

Car does not throw out any smoke maf sensor and all pipes have been checked for splits diagnostic shows all to be ok,revs ok on idle,sounds a bit rough/slightly noiser than normal,and heavy on fuel consumption

Any ideas? its a 2001 gt tdi 115 bhp pd engine done 120k.
Can anyone also tell me what that round plastic ball like thing on the front of the engine is and what it does? Car has driven me nuts!