2006 c230 engine light and rough idle
 

Hello all. Had my car just over a year very clean well looked after bought it at 143,000 on the clock with full log book services done on time to it.
Now my issue appears to have started this morning on a normal drive to work. Once the car was heated up I was coming to a slow down at a roundabout as the speed dropped the car stopped driving smoothly and started to shake. Not excessively rough just noticeably. After passing through and going back up to speed it dissapeared. Didn't happen again at the next round about. 10 minutes later as Im pulling up to a set of lights and slowing down it comes back. This time the engine light flashes 3 or 4 times before solidifying. From here Im probably another 10 mins from work. So I complete the drive fairly standard. Light remained on until I had parked. Stopped the car and restarted it later to see if the issue still occurs. Which it did. But the engine light remained off. The other thing I noticed was this shake only occured below 50km/h so once it cleared that it vanished. I work next door to a mechanic so I'll be getting him to run a diagnostics check quickly to see what tripped up the engine light. That aside. Has anyone got any ideas what and potential causes for this problem are?

Hello and welcome to the forum! The diagnostic check should give you a pretty good assessment as to where to look. Does the issue happen only during braking or when at a specific speed only?

Only at low speeds. Its not a vibration that comes through the steering wheel more the body itself.
That said the diagnostic was run and it came up with a report of misfiring in cylinder 4.
So the mechanic has suggested that with that particular information Ive given him that its most likely along the lines of either the coil or spark plug needing replacement on that cylinder in particular.

Glad that the diagnostic assessment didn't result in too much for a major repair. I'm including a link to our site's DIY tech articles for the W203 platform in case you're able to do any maintenance or repairs yourself down the line. If you have any questions, please do not hesitate to reach out to us and we'll be happy to assist.

Mercedes-Benz C-Class W203 (2000-2007) Technical Articles – C320 E320 ML320 CLK320 SLK320 – Pelican Parts