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MB Paul
MB Paul, Mercedes Technician
Category: Mercedes
Satisfied Customers: 3567
Experience:  Qualified Mercedes Benz Diagnostic Technician - 20+ years experience - Workshop Foreman for Mercedes
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I have a 2005 C230 Kompressor coupe with about 135,000 miles

Customer Question

I have a 2005 C230 Kompressor coupe with about 135,000 miles on it. This is the first time I have had any problems with the car. The car doesn't overheat, no leaks anywhere and in good shape. My problems started when the car wouldn't accelerate on the highway and the check engine light was on all the time. A shop that I trust said it is probably the mass air flow sensor. So, even though the MAF did not look bad I replaced the mass air flow sensor and both O2 sensors (post and pre-cat) but the car still did not run very well (limp mode). I took it to the shop and they said the codes read the catalytic converter had to be replaced. Logic tells me that if the O2 sensors were bad, sending false data to the computer and/or the MAF sensor was bad, then fuel could have trashed the catalytic converter. So I replaced the catalytic converter. The battery happened to go bad, this was the original battery, so I put a new battery in it too. I need to see it through.
The check engine light is not on any longer and the car idles rough in the driveway. I bought a code reader and connected it. I saw the error codes from before I started the work. Before I started the car, I cleared the codes and wanted to start from scratch. first the code reader said there were no errors, but no difference in operation. I just completed a compression check and all cylinders seemed to be fine; 1=120 psi, 2=122 psi, 3=120 psi, 4=120 psi. I would almost wonder if there was something wrong with the gauge except for the one 2 psi difference. I did notice the well on 1 & 2 had oil up to the top of the spark plug. I think this probably come from me previously adding oil at some point. The code reader now says "misfire on cylinder 2". The motor starts up fine and idles rough My code reader is capable of displaying real time data, trending PID, saving and printing. So I left my code reader connected as I was driving. A lot of data and still no error codes come up, but I don't know how to decipher the information on the screen as the car is running. Except for the obvious readings like RPM, speed, and various temperatures, I really don't know what I am looking at but I saved it and ran PID trends.
Submitted: 12 months ago.
Category: Mercedes
Expert:  David Gieswein replied 12 months ago.

Good morning my name is ***** ***** I am an ASE Master certified tech. I am very good at engine performance and diagnosis of a variety of driveability concerns. How can I help you?

Customer: replied 12 months ago.
I was just paired with another expert from "Just Answer" and required another deposit in addition to case 16588619-3. I still have a deposit waiting and additional money requested? This already is not going well...
Customer: replied 12 months ago.
I have responses from 2 different mechanics and my account shows $42 credit, another $31 that "has not been charged yet", asking for another $26 for this entry, and I haven't been given one piece of usable information yet. Where is this going??