2011 E90 328 troubleshoot P0303 cyl 3 misfire

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nj325ci
Posts: 170
Joined: Wed May 21, 2008 9:38 am

2011 E90 328 troubleshoot P0303 cyl 3 misfire

Post by nj325ci »

Got the above code after the service engine soon light came on and engine began running rough. First thing that comes to mind is the coil but before I start moving parts around to isolate the issue would anyone suggest a particular pecking order of things to check?

50,000 miles
No other symptoms like this until now

Thanks, Bill

colin
Posts: 625
Joined: Thu Aug 11, 2005 5:09 pm

Re: 2011 E90 328 troubleshoot P0303 cyl 3 misfire

Post by colin »

ima go out on a very short limb and say swapping coils is the quickest/shortest method of troubleshooting your problem, especially since you have a tool that tells you which cylinder is misfiring. I hope you find a quick resolution!

nj325ci
Posts: 170
Joined: Wed May 21, 2008 9:38 am

Re: 2011 E90 328 troubleshoot P0303 cyl 3 misfire

Post by nj325ci »

Thanks Colin. I'm going out on that limb tonight

RealM3E30
Posts: 979
Joined: Fri Jan 14, 2005 7:55 pm

Re: 2011 E90 328 troubleshoot P0303 cyl 3 misfire

Post by RealM3E30 »

Buy 2 while you are at it, I always keep an extra one on my bench 8)
91 E30 M//3 GQ
88 E30 M//3 TR
07 E91 328XIT
12 E70 X5D
16 F31 MSport Wagon
71 2002 Vintage Race Car

nj325ci
Posts: 170
Joined: Wed May 21, 2008 9:38 am

Re: 2011 E90 328 troubleshoot P0303 cyl 3 misfire

Post by nj325ci »

Great idea. I did order two. AutohausAZ.com has the oe Bosch replacement for $20 a piece!

sgoatley2001e46
Posts: 391
Joined: Thu Jan 10, 2008 4:49 pm

Re: 2011 E90 328 troubleshoot P0303 cyl 3 misfire

Post by sgoatley2001e46 »

Just trying to follow-up on this post. Did the replacement coils resolve the issue? I ask because my 2009 328i started hesitating today on acceleration. It's an automatic with 90K miles. I've done the trans fluid at 33K and 63K miles, and due again very soon. I can replicate the issue in normal drivemode, but not in sport or manual. Hoping its something more simple like coils, or even a fuel pump/filter. (I have the N51). Thoughts?

nj325ci
Posts: 170
Joined: Wed May 21, 2008 9:38 am

Re: 2011 E90 328 troubleshoot P0303 cyl 3 misfire

Post by nj325ci »

Yes, replacing the coil solved the issue for me. No problems since. Pulling the error code was the key. Then, when it was specific to one cylinder, swapping coils and seeing the error follow the bad coil to another cylinder made the cause apparent

sgoatley2001e46
Posts: 391
Joined: Thu Jan 10, 2008 4:49 pm

Re: 2011 E90 328 troubleshoot P0303 cyl 3 misfire

Post by sgoatley2001e46 »

Thanks for verifying. I'm going to see if I can get my hands on a code reader today. I don't think the one for my previous e46 will work on the e90. That said, no lights are on the dash (at least not related to this issue), so I'm hoping a code is stored. Obviously, I'm hoping it's something as simple as coils. Thanks again.

colin
Posts: 625
Joined: Thu Aug 11, 2005 5:09 pm

Re: 2011 E90 328 troubleshoot P0303 cyl 3 misfire

Post by colin »

I've got a laptop with INPA on it if you can't find a code reader right away.

sgoatley2001e46
Posts: 391
Joined: Thu Jan 10, 2008 4:49 pm

Re: 2011 E90 328 troubleshoot P0303 cyl 3 misfire

Post by sgoatley2001e46 »

Thanks for the offer, Colin. I ended up using a code reader from Advanced Auto this morning in a pinch. Nothing came up, and nothing was stored. The mystery continues, but after speaking with a guy at BMW Roxbury, he feels confident it's a coil. Obviously, we didn't have the car on the lift or plugged in, but it's probably the safest route. Just a matter of figuring out which one since the computer isn't identifying a misfire.

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