mfotovati

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

outaurleague

I just had this problem last week. Same codes, come to find out it was the plug wires or something like that. Damn things cost me a total of 400$ Hope this isnt your case, but i would try the plug wires and anything electrical in that area.

Sorry for the lack of techinal definition - But i hope this helps, i will run out to the car and get the repair report after lunch to see if i find anymore information.

C230SportsCoupe

MAF, yet usually you get other codes like 017X indicating running rich.

Spray the MAF with some electronic contact cleaner and see if that helps, if it does, then time to start saving the $350 for a new MAF.

A dirty MAF will work well when hot, so if the rough idle is mostly at startup I bet its the mAF. After highway driving, no clue.

You're at about the mileage when the MAF is due to be replaced.

outaurleague

Yeah that too, i didnt think about that, due to my car only have 46k.

mfotovati

Thanks guys for your fast reply .MAF is not important at this point because I just have misfire in one cylinder.any one here has a access to DTB.I've just read some stuff in service manual about some defective engine that need to be fix if customer complain .I do not know my engine is part of that or not .this is my engine number :27194810067654 (you guys know this as a 217.948 ) as you know mercedes solve some problem step by step for this engine .My question is :this kind of stuff fixed in this engine or not .I really appriciate if somebody can give me some information about this as well.

amdeutsch

You are talking about 90k km; correct? Please keep in mind that CA may be different than US in the way your problem may be handled.

mfotovati

Yes ,90000 Km .

mleskovar

Did you swap/replace primary wire #2?

jedcred

We had a similar problem in one of the MLs: rough idle with a misfire code. Turned out to be the coil pack. Could also be the plug wires, which we replaced just to be on the safe side.

mfotovati

I changed all four spark plugs . I swapped the coils between cylinder 2 and 3 and also 2 and 4 after to see if the problem followed the coil, it did not. there is no wire between coil and spark plug .what is primary wire?

C230SportsCoupe

I have a misfire in just 1 cylinder too, yet also the 0172 (I think) code indicating running rich.

Has your gas mileage gone to hell? I put money on its the MAF, and a quick spray with some cleaner wouldn't hurt to try and take 5 mins.

mfotovati

Gas milage is fine so far.

outaurleague

i still think my gas miles suck. But coming from a ITR, you can imagin why. Been riding the CBR all week. a whopping 36mpg!

alexhui

Suggestion:
- change all plug wire set (6 pair) $30/pair
- change all spark plugs (6 pair) $10 each
total parts $300.

My problem went away immediately.
If problem happens again, consider to change coil pack.

Mercedes

Im glad I stumbled upon this thread I also have the same problem, I have 93k miles and its a misfire in cylinder 3 they said it was carbon build up in the exhaust valve and said I needed a head job and quoted me $3,000 to do it, I'm not to sure its carbon build up I think it could be the MAF like other members have stated. I hope you find a solution so I could as well know how to fix this problem.I was also thinking of taking it to an independent Mercedes shop to get a second opinion on things

mfotovati

I booked an appointment nect week .I will let you know what is happening.MAF if not a problem at this point because you just have miss fire in one cylender not random misfire .

C230 Sport Coup

Ever heard of an Italian Tune up?

You need to get out, run that sucker in hi rpm's, long trip etc.
blow the carbon out. 3 grand? ha.
Take a long trip, or spirited run somewhere.
Extended long rpm's seem to work best.
Drive on the freeway, perhaps downshift, and keep it at or just above 4K rpm .

C230 Sport Coup

In regards to the P0302 code, I find it hard to beleive it's not the
coil pack.
Oddly enough, it seems the 2nd cylinder seems most prone to misfire.
Both times mine went it was #2.
If your car has 90K miles, it's likely that all the coil packs are marginal.
It's possible that putting a cp with 90K miles from another
cyl. still throws a code.
CP's are 30 bucks online. Maybe worth it to try replacing it?
Just a thought. M111 seems to have fairly common issue with these CP's.

Mercedes

yea that's what my father in law suggested I've done that I drove a total of 200+ miles all 3K rpms and up shifting high etc.. I've even put in carbon cleaner every once in a while, still nothing. I don't think it could be carbon build up, seems to me the dealership is ****ing me over like always I'm going to go and take it to another shop and get a second opinion and suggest they change the coil pack?

mfotovati

Mine is still under waranty even for CP so I rather they do it and replace .I will let you guys know what is happening.I think the peroblem is some how with valve guide and these things .I 've heard new valve is smaller to prevent this kind of sticky problem on M271

mfotovati

Problem fixed by dealer:
Replaced cylender head , valve ,spring . Thanks guys