hi all,

ive fixed everything on my 2002 vectra c 1.8
took it for an mot today and it failed on the lambda reading 1.11
the other readings looked so low they were untrue?

co 0.00
hc 4

i like the garage and the mot guy is a good and fair but i dont trust there machine
a month ago i took my girlfriends picasso for its mot and it passed lambda 1.0 but checking the readings today it also had a co of 0.00 and hc of 4 ??
i remember about 4 years ago i took a freelander there which also failed the emmisions but i took it to a mate of mine in another garage and it passed the emmisions well within tolerance??
i take quite a few cars there and all have passed except the freelander and this vectra? but i cant believe all the co and hc readings are always the same??
i dont want to pay for another mot were my mate workes just to pass the emmisions as they are over strict and it may fail on something else.
i checked the lambda sensors, the front one was blipping 0.2 to 0.8 which is correct, the lower one was stuck on 0.45 so i replaced it at a stupid cost, the retest is now at 1.08
the exhaust is fine and the intake is fine.
any ideas/ tricks to get the lambda down a little?