My '07 x5 4.8i has been running terribly with a misfire in cylinders 4, 5, and 8. The misfires start when I decelerate, and sometimes when I accelerate. My father wants to change the mass air flow sensor, but I don't believe that is the problem. My reasoning for this is I have cleaned the MAF and it hasn't had any change in the way it runs. I want to change my spark plugs and ignition coils because they have never been changed in the 137 thousand miles that are on the engine, but my father says I should be looking to change my crankshaft/camshaft sensor, or my throttle position sensor. What should I do?