high lambda reading

[chrism]

Would really appreciate some input on this one.

Did an emissions test today in my quest to get this muthafuka registered here.
Both my CO and my HC values were spot on but the lambda values were at around 1.22.This means that its running well lean.I checked the plugs and they were a nice light brown colour.The car is also hesitating under part-throttle.Never under full.
Ive done some checking myself regarding the matter but am interested to hear some other points of view.

Anyone?

 

[Fusion Ed]

Check for air leaks on all the vacuum pipework for a start, possible faulty lambda sensor as well.

 

[chrism]

I get my new plugs 2morrow.I believe that the plugs arent igniting all the fuel so there is excess fuel in the o2 reading.The sensor reads this as a lean mixture.
I checked with NGK today and the plug gaps for the pfr7b9 should be 0.6mm. My plugs have been at 0.8.After I reduced the gap to 0.7 it felt better but not 100.
Hopefully the hesitation/cut out disappears after this.
Otherwise lokks like a new lambda!

Is there anyone out there who has installed a universal lambda?
Which one if so?