trouble with emissions on my polo 6n2 1.4 16v

[Rawson]

Hi all,
basically my polo (2000) 1.4 16v AHW engine failed its mot for the second time in a row, the first mot i had for the car it failed on all emission tests, so me and my mate put a brand new catalytic converter on it and also a new lambda sensor as the old one was damaged. Took it for the second mot yesterday and it failed on emmisions again! here are the refulsals -
1. exhaust emissions carbon monoxide content after 2nd fast idle excessive (7.3.D.4)
2. exhaust emissions hydrocarbon content after 2nd fast idle excessive (7.3.D.4)
3. exhaust emissions lambda reading after 2nd fast idle outside specified limits (7.3.D.4)
So what else can i do to make the emissions better?
any help would be much appreciated
thanks

[alexperkins]

Check the wiring on the front lambda sensor which it plugs into . It often degrades and causes problems like this.