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I have a problem with my 330 ci, its got such a rough idle when the MAF sensor is plugged, to a point when i cant even hold idle and it stalls but it is as smooth as normal when the MAF sensor is unplugged. This is the initial problem that caused all my other problems that i now need to fix as i then decided to drive it with the MAF sensor unplugged but now the engine has a pinging knock everytime i accelarate especially when the engine is under load and needs to perform. Overall i have also noticed that the car does not perform as well as it use to.

Please help me diagnose all possibilities and try to fix this as i really feel like very soon its going to give in and stop working completely.
 

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You need to get a scanner and read all the codes.

Any idea we have would be a shot in the dark without scanning the computer.


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You’ve wasted good money on a new MAF. The cause of the rough idling is vacuum leaks. The first step in diagnosing a problem is to scan the engine computer (DME in BMWspeak) for codes. Always.

Why did unplugging the MAF cure the idling problem? Unplugging the MAF causes the DME to go to an overly rich fuel/air mixture. This masks vacuum leaks. Have the intake smoke tested.
 
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