had m.o.t yesterday passed

prob is car was running great when went there, then they adjusted CO to get the pass ! now set at 2% they didnt tell me what was set at just said sky high ! car running rough and srtuggling tick over now im running an ahmed bayjoo chip stage 3 this was done few years back now and the older chips like to run rich. want to have a tweak at it until go and get set up done. which way to richen clockwise or anti clockwise ?
car is 2wd ecu has white screw. none of local garages near me want to help by just sticking probe up while i adjust !
any help appreciated
thanks