Rough Idle

2006 BMW 330
91,500 MILES
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PAUL323
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  • 2 POSTS
My SES light came on and my car started idling rough. It is giving me a P1415 code which says it is a secondary air system in bank one. My car does not have a secondary air system. I checked for leaks in the manifold, sprayed some carb cleaner around the intake manifold to see if there was a intake leak, no change. I disconnected each coil pack while it was running and the car ran worse, I changed the plugs and still get a rough idle when stopped at a light. My o2 sensors seem to be putting out around the same voltage, the fuel trim numbers are higher than normal,
-28% on the STFT and +26% on the LTFT. Could it still be the o2 sensor on bank 1 or is it a software problem.
Aug 29, 2011 at 12:38 PM
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JACOBANDNICKOLAS
  • CERTIFIED EXPERT
  • 110,175 POSTS
I have seen this problem before and it is caused by the MAF and a dirty throttle bore. Here are toe guides and diagrams below to show you how to fix the problem.

https://www.2carpros.com/articles/how-to-replace-a-mass-air-flow-sensor-maf

and

https://www.2carpros.com/articles/throttle-actuator-service


Please run down these guides and report back

Cheers
Aug 31, 2011 at 1:27 AM
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PAUL323
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I did what you said and cleared the codes the throttle bore was filthy the engine has never run so good. No check engine light yet I will let you know if I have more troubles, thanks again :)
Sep 10, 2011 at 7:18 PM
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JACOBANDNICKOLAS
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Use 2CarPros anytime, we are here to help. Please tell a friend.

Cheers
Sep 10, 2011 at 7:23 PM