Mercedes c300 shaking at idle misfires running lean
6 Answers
My Mercedes c300 sport 2010 v6 has emissions light on. Car was shaking at idle or rough idle in park. Tried to drive it... it wouldn't get power acted like it wanted to cut off. Took it home took gas cap off it gained power stopped shaking. Couple hours later it started shaking (rough idling) again but only in drive with foot on brake not in park or reverse it wouldn't do this it was smooth. When I drive it has full power rpms are normal everything smooth I get it hot above 80 on dash I come to a stop in drive with foot on pedal it will be smooth then start rough idling after a couple of seconds. I go to take off again everything seems fine. It seems to come & go but it hasn't went back to the sluggish no power. Any ideas I ran a diagnostic test it is misfiring on 3 & 6 and is running lean. Please help it is very annoying & I need to fix this asap I'm trying to sell & never buy a Mercedes again
Auto_Centric answered 8 years ago
Mercedes are decent but only the V8s cars not their little engines or base cars.. anyways what are the codes? what is the real time live data display's on your scan tool . better yet have it checked with a Sprinters Xentry tool
Didn't flash any codes just come up as misfire on 3 & 6 & something about bank & lean or something? I got it tested at O'reillys. Someone steered me toward coil packs...could two coil pack be gone since I am misfiring on both cylinders & it running lean? I haven't checked plugs or these yet I have to get some tools & time
Auto_Centric answered 8 years ago
Lean is normally a Hego (heated exhaust gas oxygen) sensor issue, upstream bank one .. read the plug are they clean "white" If so its lean, change the upstream 02 sensor(s) 2010 3.0 V6 should have coil on plug, you have a coil pack? Oh your saying two coil on plugs cyl 3 cyl 6 bad.. do the 02 sensors first then rescan.
My Mercedez Benz 300C 4matic has been misfiring the same until the other nite it finally just gave out and didnt start up again I had to tow it bak home I mean the OBD gave me 14 codes on the first diagnoses so I took it off and 1 min later I diagnosed again ND it came back with only one code misfire on cylinder 4. So the Benz is parked I need help figuring it out ASAP a few mechanics say its coil pack ?
