I have a 2004 c230 kompressor sedan...

The check engine light came on, ran the obd2 scanner said p0303.. cylinder 3 misfire... Changed out the spark plugs and wires.... reset the check engine light...

Light came back on... can ran rough at idle..... after cooling the car down and turning it back on, the car ran fine....... the check engine light went away on its own few days later... only to return the next day...

I notice the light comes on when the car is idling.. the car shakes at low rpms.... Once i shut the car off and restart it, the check engine light is still on but runs normally.....

Any suggestions or ideas??? already did the wires, plugs...
thanks in advance! The car has about 58k miles...

 

vacuum hose?

 

Take it to the dealer. I ignored a cylinder 3 mis-fire at idle, and guess what! Hole in piston #3 and a new engine on the way! outside of warranty, so I'm out a chunk of money.

 

i have had that problem since last july and i havent fixed it yet lol

 

well besides changing the spark plugs and wires.. i have not done anything because the light has gone off now for a few days now... So i think as long as it stays off i'll wait until the next maintenance to get it checked out..

I'm very sorry to hear about your mishap with your cylinder.. i do agree mercedes does seem to have more problems than more simple cars.. I have had a few hondas that never had any problems ever...

 

I just picked up a P0420 code today. Time to replace at least the O2 sensor that is in front of the cat first to see if it clears. 50,500 miles on it, so I guess its due.

 

well i took the car to the dealership finally.. luckily i did.. I didnt know my car was still under warranty...

Anyways they ended up doing alot of stuff... pretty much almost like a new engine.. runs smooth now!!!!!! I'm very glad i took it there and i'm very pleased!!!

 

check engine light occurred on thursday 5/07
dealer replaced left catalyst on monday 5/12 (code p207f-001)
check engine light back on tuesday 5/13
dealer ordered O2 sensor on thursday 5/15
O2 sensor to be replaced friday 5/16

 

Did the o2 sensor fix your problem? Which one did you replace?