N54 335is misfire

tsk · 04-06-2026, 01:48 PM

Hi all.

I've got a 2012 335is that ended up sitting for a year and half or so and I've recently pulled it out of storage. Obviously it had stale gas which I ran through as best I could short of draining the system. Car has close to 100k miles on it. Plugs were probably done at 50k. Car is bone stock except for a metal turbo intake.

Anywho. Car has ran for a couple thousand miles here and on Friday felt like it went to limp mode about a mile from home. Got it home and read the code which said misfire (think it was cyl 1 and 3 but might have only been 3 based on current situation). I had spark plugs sitting around so I started with those.

Pulled all the spark plugs and cylinder 3 was pretty wet. Assume it was fuel and the exhaust smells like fuel when it runs for a sec. Replaced everything started for a sec, engine code came back almost immediately. Swapped coils 3/4 and same result. Pulled plug 3 again and it's wet, not drowning.

I'm assuming I have bad fuel injectors. Index is 9 on these. Seems as though this is somewhat common and gonna guess stale fuel might have contributed. Any other thoughts before I drop some $$$? I can get by replacing injectors 1-3? Should I replace coils while I'm at it? Is there anything else I need to do after replacing? Don't suggest a o2 sensor please.

Thanks.

TunafishE93 · 04-06-2026, 03:01 PM

I wouldn't worry about coils, i believe you can send in your injector for rebuild.. be a fraction of the price then a new one! I would just send in the one that is acting up. Are you getting a rich code?

tsk · 04-06-2026, 03:08 PM

No rich code. Just a cylinder 3 misfire. When I pulled it, it was definitely a lot wet. Bad enough I'd hate to drive it long. And misfiring enough that I immediately felt it.

Problem with a rebuild is time. I am assuming it'll take a couple weeks. I might pull the first bank, and send em in for a rebuild and do the second bank at a later point if that fixes everything up. Getting to em is pretty easy.

tsk · 04-06-2026, 03:13 PM

Also seem as though rebuild may not be an option for the earlier versions of the injectors (I have index 9). Found one place and they say:

Important BMW Piezo Injector Service Notice
This service is intended for BMW Index 11 and 12 piezo injectors only
Earlier index injectors are not supported due to known failure rates

04-06-2026, 01:48 PM	#1
tsk Registered 0 Rep 3 Posts Drives: 2012 BMW 335is Join Date: Apr 2026 Location: Wisconsin iTrader: (0)	N54 335is misfire Hi all. I've got a 2012 335is that ended up sitting for a year and half or so and I've recently pulled it out of storage. Obviously it had stale gas which I ran through as best I could short of draining the system. Car has close to 100k miles on it. Plugs were probably done at 50k. Car is bone stock except for a metal turbo intake. Anywho. Car has ran for a couple thousand miles here and on Friday felt like it went to limp mode about a mile from home. Got it home and read the code which said misfire (think it was cyl 1 and 3 but might have only been 3 based on current situation). I had spark plugs sitting around so I started with those. Pulled all the spark plugs and cylinder 3 was pretty wet. Assume it was fuel and the exhaust smells like fuel when it runs for a sec. Replaced everything started for a sec, engine code came back almost immediately. Swapped coils 3/4 and same result. Pulled plug 3 again and it's wet, not drowning. I'm assuming I have bad fuel injectors. Index is 9 on these. Seems as though this is somewhat common and gonna guess stale fuel might have contributed. Any other thoughts before I drop some $$$? I can get by replacing injectors 1-3? Should I replace coils while I'm at it? Is there anything else I need to do after replacing? Don't suggest a o2 sensor please. Thanks.
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04-06-2026, 03:01 PM	#2
TunafishE93 Major 557 Rep 1,308 Posts Drives: BMW 335i Join Date: Dec 2019 Location: NV iTrader: (0)	I wouldn't worry about coils, i believe you can send in your injector for rebuild.. be a fraction of the price then a new one! I would just send in the one that is acting up. Are you getting a rich code?
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04-06-2026, 03:08 PM	#3
tsk Registered 0 Rep 3 Posts Drives: 2012 BMW 335is Join Date: Apr 2026 Location: Wisconsin iTrader: (0)	No rich code. Just a cylinder 3 misfire. When I pulled it, it was definitely a lot wet. Bad enough I'd hate to drive it long. And misfiring enough that I immediately felt it. Problem with a rebuild is time. I am assuming it'll take a couple weeks. I might pull the first bank, and send em in for a rebuild and do the second bank at a later point if that fixes everything up. Getting to em is pretty easy.
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04-06-2026, 03:13 PM	#4
tsk Registered 0 Rep 3 Posts Drives: 2012 BMW 335is Join Date: Apr 2026 Location: Wisconsin iTrader: (0)	Also seem as though rebuild may not be an option for the earlier versions of the injectors (I have index 9). Found one place and they say: Important BMW Piezo Injector Service Notice This service is intended for BMW Index 11 and 12 piezo injectors only Earlier index injectors are not supported due to known failure rates
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