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  1. The Dreaded PO171 / PO174 DTCs... Vacuum Leak or MAF issue?

    General E46 Forum
    Fairly new here and 1 month owning a pretty nice 2003 330ci convertible. These 2 codes popped up twice now; looking for advice as to whether look towards a vacuum leak(s) or a faulty MAF sensor? Leaning towards the MAF because both times the codes dropped during highway speed driving (never...
  2. Help Im confused

    General E46 Forum
    Ok well i know there has been a million threads about po171 po174 but I cant seem to find my answer. I drive a 2001 bmw 330ci. Replaced Valve cover Gasket , spark plugs, Both intake tubes, all of my little vaccum hoses, replaced disa gasket, ofhg gasket, air filter. 2 things i havent done are...
  3. Does on board computer have to be reset on car or does po174 still exsist?

    General E46 Forum
    Help please! My check engine light came on a couple of weeks back. I used my CarMD (OBD reader) diagnostic reader on my 2003 330Cic and it gave a reading of po174 (only). So I cleaned the MAF and also found a tear in the oil separator hose going to the dipstick so I replaced that hose also. The...
  4. exhaust clamps

    General E46 Forum
    I noticed some loud rattling grinding sound when i got in my car on the way home from work today. thought it might be something bad, it would happen when i put my car in reverse or start to drive or turn the wheel. i stuck my head under and had my girlfriend mess around with the wheels and pop...