Good morning all,

I have been having this problem where my RPM’s will surge, ie car feels like it is chugging along from time to time, and it has gotten progressively worse over the last year or so. My first thought was of course the fuel filter which I promptly replaced. Problem still there so I went over the diagram with my parts guy at the dealer. I found that there is a secondary filter so I pulled and inspected that. Clean as a whistle. So what else could it be?

The problem typically happens when I am on the highway around 75mph with the cruise on or off. If I get the rpm’s up over 3k it goes away. It also happens on city roads at lower speeds and will stop with a good mash on the accelerator. I have video that I can post later of my tach while it is doing this. It usually surges up and down about 100 -300 RPM’s and the car feels like it is chugging.

Any pointers are greatly appreciated!

- Bryan

Is this the turbo or N/A version?

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

It is the NA.

If after the throttle is increased it would have to be something blocking fuel delivery and not the injection pump. This one really has be baffled.

Is this a 50-100 rpm surge that occurs at a constant 1500 to 2500rpm when crusing?

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

Sounds about right. Is this a common issue? Hopefully a quick fix.

Humm, this is my second post in 5 minutes and I'm going to say the same thing... Hopefully it might help. did you look at the tank strainer? They have a bad habit here in the UK to be really badly clogged. I had to do mine twice, the seconf time I chop it off, to hard to get access.
Olivier

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E300TD year 2000. RUSTY SOLD
cost a fortune to maintain on the road
but run well on WVO
Second Merc died due to corrosion ( NOT rust) How can mercedes get away with that for so long?
Third lasted a month then went away...
Fourth now... Corroded too...

96 surge

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'98 E300 turbodiesel

Thanks guys! I will read over everything when I get home today and let you know how it went. Thanks again.

- Bryan

Do a search on surging. Its most likely related to the intake flaps and or EGR, or a vacuum leak.

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Dennis
2006 E320 CDI Black/Black Leather. Nav, HTD Seats HK stereo 32000 miles.
2000 VW Passat 1.8t 300,000 miles as of Dec 09, 2009 original owner
1997 E300d Silver 300,000 miles As of Jan 05, 2010
3rd owner SOLD

When I recently changed the glow plugs there was this nasty black goo that was inside both the intake and around the valves. I did my best to eliminate as much of it as I could but could the cause of this also be the cause of the surge or would the cause of the surge be the cause of this?

What should I check first knowing that there was this black goo in the intake? I would like to check all of the easy things it might be before pulling the gas tank and checking the screen.

Thank you again to all that have contributed to solving this issue!

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Join the organization at VintageBenz.org

Current vehicles the wife and I are restoring:
1966 W111 230S - near completetion
1976 280C - the wife's toy
1981 300SD - is already a beauty

Did you read the thread Lupin linked to above in post #7?

The surging is common on your model and it almost always is related to a fault in the EGR/Resonance flap system. First step is to clean everything so it all operates freely and properly.

There are lots of threads about how to clean them, just use the search function or ask specific questions about it. Once the flaps and EGR valve are clean and operating properly retest and see if the surging is still present.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz