Lately my car has been losing power under load, most of the time it sounds like a tractor the past 6 days & very high shaking of engine, sounds fine on idle at around 900-1000 rpm, if it exceeds that then shaking & tractor sounds. here's what I've done so far: Cleaned injectors Changed x4 spark plugs Diagnosed with no fault codes to report ignition coils or coil packs are apparently fine No change what so ever except occasionally it runs smooth, misfire, smooth, misfire, smooth, misfire! not to mention the jerking! What I'm checking next: ignition leads MAF (Would it be safe to disconnect this temporarily?) fuel pump is there anything else I should have checked? is this a common fault? it's a V 1999 1.6 automatic saloon.