Another misfire thread - MBWorld.org Forums

Dec 2, 2022 | 06:22 PM

teknic

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Joined: Jun 2016

Posts: 101

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From: Bluffton, SC

2009 W211 E63, 2000 Yamaha R1

Another misfire thread

Hi all,
I pulled into my office’s parking lot two days ago and the engine started misfiring while going back and forth straightening the car up. Shut it off and back on again and moved the car to another spot and more misfiring happened. CEL came on and stayed on. Didn’t feel driving the car home in that state so had it towed. Pulled the codes and got P0300(random/multiple misfires) and P0305-P0308( misfire detected in cylinders 5,6,7,and 8. Pulled the spark plugs from the both sides and the ones for driver side all look dark and nasty. The passenger side ones seemed okay(side by side picture of one from each bank is attached). Switched coils for cylinders 3 and 4(passenger side) with 7 and 8 from driver side, erased codes, ran the engine and heard a big detonation and shakes. CEL went away and came back on after a few seconds. Turned it off. Got out of the car and I could smell gasoline. Pulled codes again and got P0307 and P0357. Any ideas what the cause could be? 09 E63 with LTH and catless. 129k miles on odometer. RENNtech tune. Upstream O2 sensor for passenger side was replaced 15k miles ago. Thanks in advance.