MOT fail on emissions

[turboshed]

Had an MOT earlier anf failed on windscreen (was to be replaced today but they did not get the rubbers/trim so its to be done tomorrow) and emissions of 5.89%. I had the idle at about 850RPM and was wondering if i put it down to 750RPM if it will help? Another thing is i got optimax with a millers cvl turbo octane booster so i think this wont help either and wondered if putting super unleaded not optimax in will help get them emissions down too?

Current engine specs are:
HD stage 3 chip, T25H, Z32 maf, NGK BCPR7ES aprk plugs new in today, 440 injectors, frount mount intercooler, apexi filter and stainless intake pipes, 3" turbo elbow back exhaust system, KA24 throttle body

Any help and advice would be greatly appreciated
thanks

[skyshack]

5.89% on 850rpm idle test? Or have they done a high idle test?

Do you have a Lambda? Or do (did) you have a mixture screw on the AFM?

[Jez]

Its important to get the idle setup as per the service manual and make sure the ign timing is correct too.

[turboshed]

skyshack: the tester just said it was at idle and i dont have a lamba and never had. not to sure about the screm on the AFM what would it do if i do have one?
Jez:Goodpoint about the ignition timing i will endeavour to check it when i can get my hands on a timing gun