P301, Cylinder 1 Misfire
Thread Starter
Newbie
Joined: Aug 2015
Posts: 6
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From: Austin, Tx
2009 ML350
P301, Cylinder 1 Misfire
Hi All. Love the forum and appreciate any advice. Thanks in advance!
Couple weeks ago did the typical oil change and replaced air filter on 2009 ML350. Saw some bugs and mild debris in the air cleaner, so washed it out and pretty sure was fully dry before installing filters and putting back. At the time, noted rattle on passenger side of engine block. Does not increase with revving, and disappears behind engine noise.
Monday, due to gas station out of gas (in Texas) near our house, wife chanced it and came home instead of going to another. Used gas from the gas can to make sure enough to get to station in the morning, was probably about 4 months old. No problem, but then stopped at gas station Tuesday and all they had was regular unleaded. She got a quarter of a tank, no problem. Later added another quarter with super (dont ask me why she didnt just fill it up). Wednesday morning, she started having check engine light and engine running rough particularly at idle and initial acceleration. At higher speed less noticeable. Pulled codes and it was engine misfire detected cylinder 1, P301. It was due for plugs, so went ahead and replaced them. Still immediately same code, and same rough idle. I have a new coil on order coming Tuesday, nad have a hard time believing it was the gas since it wouldn't keep coming up cylinder 1, would it?
Question: Am i missing something? Is that rattle something more serious with the engine? Did the fuel mess something up? Any insight appreciated!
Couple weeks ago did the typical oil change and replaced air filter on 2009 ML350. Saw some bugs and mild debris in the air cleaner, so washed it out and pretty sure was fully dry before installing filters and putting back. At the time, noted rattle on passenger side of engine block. Does not increase with revving, and disappears behind engine noise.
Monday, due to gas station out of gas (in Texas) near our house, wife chanced it and came home instead of going to another. Used gas from the gas can to make sure enough to get to station in the morning, was probably about 4 months old. No problem, but then stopped at gas station Tuesday and all they had was regular unleaded. She got a quarter of a tank, no problem. Later added another quarter with super (dont ask me why she didnt just fill it up). Wednesday morning, she started having check engine light and engine running rough particularly at idle and initial acceleration. At higher speed less noticeable. Pulled codes and it was engine misfire detected cylinder 1, P301. It was due for plugs, so went ahead and replaced them. Still immediately same code, and same rough idle. I have a new coil on order coming Tuesday, nad have a hard time believing it was the gas since it wouldn't keep coming up cylinder 1, would it?
Question: Am i missing something? Is that rattle something more serious with the engine? Did the fuel mess something up? Any insight appreciated!
Thread Starter
Newbie
Joined: Aug 2015
Posts: 6
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From: Austin, Tx
2009 ML350
I didnt think a clogged injector would produce that code.
MBWorld Fanatic!
Joined: Oct 2011
Posts: 7,107
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From: Bronx, N.Y.
2002 ML 320 & 2006 ML500
Understand about the filter.
As to the injector, they have their own codes but the code would only be stored if the open injection time was faulty at idle or higher RPM and cannot tell you if it is clogged.
Are you sure there aren't any other codes like P0300?
As to the injector, they have their own codes but the code would only be stored if the open injection time was faulty at idle or higher RPM and cannot tell you if it is clogged.
Are you sure there aren't any other codes like P0300?
Thread Starter
Newbie
Joined: Aug 2015
Posts: 6
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From: Austin, Tx
2009 ML350
Thanks again for the suggestion. Replaced the coil on that one cylinder, and back to normal! $50 and about 15 minutes of work. No more codes! Runs fine. I guess the fuel issues were just a coincidence.
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2014 Smart ForTwo Passion Cabrio
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