My 95 E420 with about 133k on the meter gets a bug up its tailpipe and will start to run very rough almost like it is down to a 4 banger! At first it was just once in awhile but now it is happening more often. When I pull up to a stop it really smells of strong exhaust smell ? But not a rotten egg smell of a converter. Will miss at the low rpm but if I am in 1st gear and get the R's up if feels like the other plugs start to fire up! If I shut it down for say a hr. or so fire it up and runs like a clock? There was a post I think on this forum where a fella had simular problem and a member replied to it ! but do you think I can find that post?? I am taking car into the shop for new swaybars and shocks on Wed. and I wanted to to talk to tech about this prob and the members idea! Would like to find a solution to this as the car runs great otherwise! So if ya all got any ID whats going on hear I am all ears!

Smokie

HAve you checked the fault codes? There's a number of things it could be - wiring harness for example. It sounds electrical/ignition related. My next step would be to see what the fault codes are saying.

Thats the weird thing! no codes !! Makes finding prob all the harder!

Smokie

It sounds to me like it is going into limp mode due to a detected misfire. Check your plug leads, or replace them, did you recently get your engine wet? When I wash my engine it does this, restarting corrects it, but then if it misfires again it goes into limp. Of course as a 95 model you may have a harness issue as well, so check that out. You may need a new one.
Good luck!
Brian

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Brian W. Heitman

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I had the same problem on my '87 300E. We tried everything electrical and fuel related. My son in law casually mentioned that he had a similar problem on his Passat. It was the COIL! I couldn't believe a coil would misfire at LOW speeds. Changed the coil, solved the problem.
Anziani

Don't forget to check your cats? Also how about the dreaded "wiring harness"?

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Regards . . . . JimF
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'94 S500 Cpe

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I had a similar problem on my 97 E420. It was only giving random misfire codes and trim codes. The car ran like crap and had zero power. When I tried to accelerate, the check engine light would flash. Long story short, it turned out to be a blocked cat. The code reader wont tell you if there is a problem with the cat but there are some diagnostic tools that allow you to read the live data from the O2 sensors before and after the cat which will give you an indication of what is going on. Hope this helps, it was very frustrating and expensive for me when I had this problem.

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With best regards

Al

Friend of mine thinks cats to! But I have hard time with that! This happens it seems like when I get in it and give her a hard blast down the the hwy! But I can shut it down for a short time it fires right up like nutin ever happened? Wish I could find that post ! Guy here had sameo prob. I think it is ign related because of the way it when it comes in it is like you hit a switch! Bang it goes! Then you drop the rpm and it runs like crapola again! I am not going to rule out cats just yet ! After reading ala's post , because the very first time it did happen the CE lite did come on ! but only the one time!

Smokie

When you say no codes - how sophisticated was your code reading - the LED light, the homemade code reader, a scanner? It seems like it must be putting off some kind of code somewhere.

I used the led one up by the firewall! nada zero zip!!

Smokie

That's only the emission related codes - you need to check the 38 pin connector - I'll bet you find something that will offer a clue.