My car is 2003 c230 with about 90k .My engine light came on and the car started idling roughly. I checked the codes and it reported a p-0302 (cylinder 2 misfire). Restarting the car cleared the rough idle, with the CEL still on (occasionally it will go through a drive cycle and clear the CEL, but only every once in awhile). So far I changed all four spark plugs . I swapped the coils between cylinder 2 and 3 to see if the problem followed the coil, it did not. I replaced the fuel filter (thought maybe the #2 injector was more sensitive then the others.)
I did this work over the course of the past two months, and the only code that was logged was The p-0302. This code was only logged at idle (the misfire never occurs under high rpm's/loads) and more prevalent after being on the highway and coming to a stop at a light shortly after exiting.I saw other people complain the same thing with the same car but I never heard what is happening finally to fix the issue .could you please let me know what is the problem ,(sensor ,fule injector ….)
Thanks

 

Is it a kompressor? Do a wet compression check, pull off the exhaust manifold and you probably see oil around the valve area, therefore you will need a new head.

 

Yes , it is kompressor . I have a service manual for this car . I am going to find out how to do this test .what do you think obout fule injector or any sensor on that area to send wroung information and then computer turn of that cylender ? Thanks

 

The injectors hardly ever go bad and the 271 engine. The misfire is most likly due to low compression in cyl# 2. It could be an injector, but if the injector was not firing you would cause a misfire at idle to full throttle.

 

my engine number is 27194810067654 .I do not know regarding to DTB stuff it is defective (spring .gasket .. ) engine or not.hope not because i really do not want dealer open the engine to replace some part inside and ofcourse too much money.

 

its a common problem , do a compression test and if it low then 99% it going to need a new head but with a wet compression check and exhaust port check you pretty much rule out the bottom end being the culprit or do a leak down test but sometimes it hard to determine where the air is leaking out of.

 

I really hate to say that "startech" is right about you needing a new cyl head. you have to do a compression test to be sure, but in my experience the cuase is from the carbon build up on the exhuast valves.

 

One more thing that i notice during these days is my coolent temp is around 95 celcuse .it use to be i belive 80 - 85 .is there any thing wroung with that.I checked coolant level and is fine.I ususally drive 1 hour in highway aroung 3000 rpm .during these days weather is aroung 20 - 25 celcuse.

 

Have you done a compression test yet???

 

Not yet. I booked the car for next week to dealer as it is under warranty for these stuff .