Engine misfire cylinder three

Tiny
JITHIN MATHEW
  • MEMBER
  • 2011 MERCEDES BENZ C300
  • 3.0L
  • V6
  • 4WD
  • AUTOMATIC
  • 75,000 MILES
Hello, I have a misfire only cylinder three. I replaced the ignition coil and spark plug for that cylinder as told by Mercedes dealership. I even swapped the coils with a different cylinder but no luck. I think it only misfires on startup. I am suspecting a leaky fuel injector. I pulled the freeze frame data from the car.
Saturday, November 2nd, 2019 AT 6:08 PM

1 Reply

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
I think you are on the right path. Do you have the o2 sensor data? If it only misses on start up then I would expect the o2 sensor (short term fuel trim) to come back to normal but start out with a rich condition so the short term should show negative then work back to 0.

Let me know if you have this and we can go from there. However, I would suggest swapping that injector with another cylinder and see if the misfire moves with it.
Images (Click to make bigger)
Thumb
Thumb
Thumb
Thumb
Was this
answer
helpful?
Yes
No
Sunday, November 3rd, 2019 AT 2:35 PM

Please login or register to post a reply.

Related Engine Misfire Content

Intermittent Misfire
VIDEO
Intermittent Misfire
Instructional repair video
Misfire Random Code P0300
GUIDE
Misfire Random Code P0300
The world of automotive diagnostics can be complex, with numerous codes and potential issues to keep track of. One of the more common engine diagnostic codes is P0300, which...