hi All, please help me.. I'm sorry that i might post this problem here although my car is a w211.. but i think maybe you guys have had experienced this kind of problem because my E class has the same engine as the w203 (M271 KOMPRESSOR)

I am really confused and need some ideas as to where to look for a weird issue that I am having with my 2004 E200 Kompressor (M271 Engine). My car has 43K miles and has the 4 cylinder engine (M271, Which is like a W203)

The morning start is a little rough on some mornings (If i didn't start the car 24 hours or left the car sitting 2 days), ie you start the car and for the first 30 secs she runs rough and a little bit misfires. then it clears and the motor smooths off and all is ok. this is intermittent, ie might happen once or twice a week.

Then when the car is on the road everything feels ok, motor responds well, just like a normal day. then, also intermittently, the car will stat to misfire when you come to a stop or idle. it feels as if she is only running on 3 cylinders.

there is no CEL/warning apart from a slight vibration coming from engine, and then suddenly will start the misfire.
you can be in full and proper town stop start driving with no problems, and then this will suddenly kick in.
to clear the problem you turn the engine off, give it 5 secs and restart it and she runs properly.
the same issue might happen again, but then again turn off and restart and she runs properly.

This misfires is only at idle, when you kick the rpm the vibration is hardly to feel..

a point to note is that once she stats this it will carry on happening UNTIL the motor has been turned off and allowed to cool down, or until you get onto a long run.
the issue does not appear to be influenced by engine temp, it can happen when motor is at full running temp or even at 3/4 running temp.
apart from cold start as described above never happens when cold.

I have checked the following;

- compression all 4 cylinders (Normal)
- changed the fuel pump and the fuel filter 3 weeks ago (due to age)
- changed ALL spark plugs
- changed ALL the fuel injectors
- changed ALL Coils
- Changed the Legendary "$12 Hose" issue
- Running on 95 RON Gasoline


Have had a Star diag done, and no error code comes up on display when the problem occurs.Is it possible a faulty MAF sensor? can it be cleaned? or maybe a o2 sensors? i dont know.. i'm just very confused...

note : At my local Mercedes dealer they said that MAF sensor Can't be clean although it can be cleaned but not going to solve the problem forever

I am very confused, sounds like possibly a fuel problem, but cannot find any reason for it...

any ideas... please HELP me guys your answer is very helpful to me.. thank you

 

Anyone?

 

Maybe pull the plugs in the morning and see if any are wet? This sounds similar to a seeping head gasket, where some of the coolant will push itself thru into the cylinder overnight (from residual cooling system pressure), so one or more of the plugs will be a little damp causing misfire at bit at startup but then clear out. How many miles on the car?

Not saying it is the head gasket, but checking the plugs in the morning might help with diagnosis. If you have a long q-tip to stick into the cylinder hole (be VERY careful not to drop it in!!!) it might help too. On a Dodge I had with similar problem, I cranked the engine just a bit with all plugs out and saw some coolant come out of the plug hole on one cylinder. That was enough to confirm what was going on.

 

Put it back on star machine and in engine systems check self adaptation values if they have shifted. Most common cause are breather hose airleaks. Service throttle body. Do a default initialization with star and it will run like a dream. Also make sure timing chain has not stretched!

 

Run some Lucas fuel system cleaner. Your fuel system may be clogged and Lucas works. Also, did you gap your plugs to spec? Did you clean your MAF??

 

Starts no problem. m271 engine. Did a rebuild. Recently changed timing chain. Valves where grinded.
Then Once idle it will start to misfire. CEl shows up and then my obd2 sensor says misfire on cylinder 2.

I have 4 new injectors
Coil packs
Spark plugs to specks
Car drives a dream until misfire. A simple reset of stop car and start again makes the problem disappear.

There is a slight oil leak. I have Rosaline head gasket sealant. I'm not in mood to rebuild engine to change head gasket.
I think that might be the problem.
At the last change of injector my obd said fault codE p2226 barometric pressure sensor.

Which could be the cause of the misfire????

Now it only shows misfire on cylinder . any assistance would be awesome.

I'm about to put the head gasket Rosaline in. Let you all know how that goes.

Thanking you.

 

I was having a stumbling issue at around 3600 RPM that was annoying me, then it finally misfired and gave me a code. I pulled the coil and plug, and also shot in some CRC MAF cleaner spray on the MAF sensor for 15-20 seconds straight and the problem went away. I didn't even remove the MAF, just pulled the cone air filter. I let it dry out for about 10-15 minutes before starting it.

Hope this helps.