89 525i code 1222

[dmc1017]

need some ideas with this problem. i had replaced exhaust have done complete valve job and thats where i begin. car has 189k and after head work started to get rough idle where rpms would vary by 300. replaced o2 sensor, idle control valve, cleaned maf and ran ohms check on it { comes back ok }, replaced air intake hose, and with car running sprayed over intake with carb cleaner and got no rise in rpm. however intermittently idle drops 300 rpm check eng comes on car may stall and be hard to restart. code comes up as 1222. dont know where to go from here without just swapping parts or taking to stealer for diagnosis.

[m1rza]

well.. i wouldn't take it to a "stealer".. id rather have a messed up car then no car !!!