hello hope someone help me i am lost

my s2 was fitted with cossy mangement but wont idle good when cold and afr is all over the place when it idle cold revs drop away and afr goes to max on gauge

tryed etrrything i can think of tested all temp sensors to me all are ok but changed them to be sure as dont cost much

also fuel pressure is 3.5 bar vac pipe of and drops to 3 on so that is ok

any one here got any idea what could be causeing this

thanks for any help