O2/Lambda sensor???

[Chambo]

Hi Fellas ive got a problem with the car,Bora 1.9tdi in higher gears say 4-6 the car is guttless i can put my foot down and it very very slowly picks up speed,ive got no fault lights on the dash and a quick look on the net makes me suspect a faulty lambda sensor,what do you think?
If that is the fault how do i know which sensor needs replacing,there are two arnt there??
Where is a good place to get one from best of all cheap?
One last Q is it a easy job to replace.
thanks in advance
Chambo

[Dolly]

i would get it plugged into Vag Com.  Search for someone near you with it, im a tad too far away

[Chambo]

Ok Dolly thanks for your reply,i'll put a shout out and see if there is anyone near me with one thanks again.Chambo