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View Full Version : 2011 BMW 328I Rough Idle Help



bpopa
07-17-2016, 01:03 AM
Any help with this will be greatly appreciated as I'm out of ideas and $1000! So I took my car into the dealership to have the oil changed and they recommended I replace all the spark plugs. about 2 weeks later the check engine light came on and the car was idling very rough and ticking in front of engine. I immediately drove home and checked the code with an OBDII scanner and it read every cylinder misfiring and camshaft timing over-retarded. I replaced the spark plugs and then decided to take it to the dealer to diagnose the misfire. They told me that the VANOS intake and exhaust solenoids need to be replaced as well as every ignition coil (apparentoy these commonly go bad). I just got home and did the repairs recommended and it STILL RUNS ROUGH at idle!* So with new plugs, coils, and VANOS solenoids apparently that still wasn't the problem. Any help/recommendations/ideas would be greatly helpful. I checked the sensor on top of the intake cover because I read the O ring often fails but mine was okay... Also checked the mass air flow sensor and it is okay. The only other thing I can think of is a vacuum leak somewhere, but as of now... I'm out of ideas and money. Your help is greatly appreciated.

E90 Lover
07-18-2016, 09:53 PM
Which engine do you have? My '08 did something similar, and it was a leaking valve cover gasket, which I learned is common on the N51. Also, the timing sensor inside the valve cover got oil in it from a gasket leak and shorted out. Rubber valve cover gasket is cheap. Sensor was $300ish.

There's a video on youtube that shows the whole repair. Reading the engine vacuum via an ODB reader will give you some insight.