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Discussion Starter · #1 ·
Ok guys... I had the rough idle as everyone has had. I replaced the Mass Air Flow and spark plugs and wires, had the egr valve and tubes cleaned and it went away. Well now I have the check engine light on with code p0400 for the egr valve and I have the rough idle again. Is this the reason for the rough idle? I mean it has to be right????
 

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99ML320 (retired) C230 530xi 911-C4
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jabus said:
ive got the same problem, gonna do a check,on the plugs ,etc , where is this, egr valve tube?
EGR valve is part of the intake system.
I recommend you click on the "SEARCH THIS FORUM" button and type in the search term "egr valve"
 

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2004 SL600; 2004 SL500;1996 SL600;2003 ML350; 1997 C280 Sport; 1987 190e 2.3 16v; 1986 190e 2.3 16V;
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Clean the EGR all you want. You'll do it again and again and again.
I know, I tried. Just buy a new one and install it. Buy the metal gasket too. It is an easy job and the part is not that expensive (use **********.com). This works, I know, I did it.

1a) remove engine appearance cover
1) Remove main air intake pipe. One screw holds it down as well as the plastic snap thing at the back of the engine. The pipe also has the rubber full flow hose leading to the driver's valve cover attached, so disconnect it. (When I did mine, the rubber was brittle and I had to change it as well. Unsnap it at the

2) Unscrew the EGR pipe at the back of the manifold and at the EGR valve.

3) Two screws hold the EGR valve on. Remove them, lift the valve, disconnect the plug.

4) clean the mounting surface.

5) Reassemble in reverse order.
 

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Discussion Starter · #5 ·
Hey guys.. Well I am in trouble. I removed the air intake pike and fiddled around a bit. I found a black rubber tube that goes into the back of the engine. I removed it, sprayed some gum out. Blew threw it. Then reattached it. Now my car idles REALLLLLLY bad. I mean its bad. What did i do? Also, i cannot find te egr valve??? Where is it?
 

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Discussion Starter · #6 ·
I pulled the codes for Check engine and I still get a P0400 but now i get a P0105. The car was shaking real bad. I guess i didnt put one hoses back on behind the engine. When I put it back on, car runs not as rough but I still have the code after clearing it. What should I do?
 

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When I called my dealership about the rough idle I'm experiencing, the guy on the phone said it's *probably* most likely the ignition coil. He said it'd run about $500 to have them fix it. I can buy the coil myself for around 150, so I have another thread started on this board asking for instructions on how to install it.

Maybe you have the same problem.
 

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2000 ml430, 99 infiniti i30 limited edition
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its easy to replace the coil. You need a torx screw driver I think a size 30. Just take off the plastic engine cover, and you'll see the coils, its like a square and the spark plug wires are hooked up to it. Loosen the torx screw and pull it out, detach the coils and it will have two spark plug cables hooked up to it, dont pull them out yet, install the new coils and making note of the orientation of the cables, pull them out one by one and push them into the new coil. Thats it
 

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2000 ml320
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hi , i have a 2000 ml320 with rough idle and lack of power, have replaced the plugs and a new MAS but its still the same anyone have any ideas what else it could be.No error codes showing up.
 

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2006 ML500 2002 ML320
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The rough idle is self explanatory, but what is your meaning of no power? Explain it a little better.
 

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Outstanding Contributor
2006 ML500 2002 ML320
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Problems like this are difficult to solve over the internet. The first thing that comes to mind is a clogged cat. converter/s or an EGR problem or a partially clogged fuel filter. But of course you will have to have these things checked out.

Please do not start replacing parts because someone has suggested it. If you take it to a mechanic (which you should) DO NOT tell him what you believe or what was suggested might be the problem. Let him tell you what he thinks and then go from there.

By the way did you recently buy this truck, if so was the problem there already?
 

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2002 ML55 AMG, 2005 Chrysler Crossfire Coupe Limited, 1999 C280
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hi , i have a 2000 ml320 with rough idle and lack of power, have replaced the plugs and a new MAS but its still the same anyone have any ideas what else it could be.No error codes showing up.
Where did you purchase the Mass Airflow Sensor from?

Was it an insert or is it the entire assembly?
 

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You guys need to be inspecting your vacuum system from front to back. When you fiddle around with the EGR, you mess with the MAF and the main air intake hose, and the breather hoses that feed to different components and valve covers. CHECK ALL THOSE HOSES. The problem with lack of power, struggling to get up a hill, misfires, all are related to cracks in the hoses, because of unmetered air entering into the cars engine. I ended up replacing all the hoses, everything related to the air system, and BAM! All my problems were solved. Wasn't an EGR, wasn't a MAF, it was hairline cracks in the air system.
 

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2005 E320 CDI, 2016 E250
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BTW...dont know who said it...but the EGRs I found were $160 a peice...not exactly cheap :) Glad you fixed your problem though. Where did you get hoses from? MB Dealer or generic by the foot replacements???
 

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2002 ML500 Silver
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Anyone have a diagram of the vacuum system to post? Maybe we can common weak spots or certain areas to check.

I just had a "lean" condition CEL so it may indeed be an air leak in my case.
02 ML500 rough idle
New plugs
Tried two different MAFs, one bosch, one generic (generic is in now).
 

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2005 E320 CDI, 2016 E250
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Would it be prudent to change the rubber hoses with silcone??
 

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Dallas, Texas
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Anyone have a diagram of the vacuum system to post? Maybe we can common weak spots or certain areas to check.

I just had a "lean" condition CEL so it may indeed be an air leak in my case.
02 ML500 rough idle
New plugs
Tried two different MAFs, one bosch, one generic (generic is in now).
Vacuum diagram is on top of the fuse box. Diagram of crankcase ventilation is here:
http://www.benzworld.org/forums/w163-m-class/1508527-please-help-i-got-oil-coming-2.html#post4050084
 
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