Intermittent idle stumble, sluggish off idle

[Red66GT]

110k miles on the car. No codes. Every once in a while, when I stop at a light, the car will start to stumble like it's going to stall. I sometimes need to put it in neutral so that it wont stall. It's almost like it's not running on all cylinders. Once the light turns green, I slip into gear, and the car is sluggish off the line, but once it gets off idle, it runs just fine. There are sometimes too when the car is running fine when I stop at the red light, then once I start to go there is a few second lag when I step on the gas and when the car starts to go.... It has happened when it's cold. It has happened when it's warmed up. Doesnt seem to be any rhyme or reason as to when it does it.

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[Musikmann]

No codes makes this a difficult diagnosis. How old are your spark plugs? Remember they are 5 years/100,000 miles replacement items. Also how long have you been running the fuel filter? Those are a 60,000 mile item.

[ohlord]

stumble on acceleration is most often the Mass Air Sensor.
Clean it with crc maf cleaner diy on www.benzworld.org w210 diy forum.
If you start getting the telltale maf codes check engine light p0170 p0173 replace the maf withan oem unit from www.autohausaz.com easy diy.

[Musikmann]

ohlord is the man so you'd better listen to him. However when my MAF failed I had a P0170 and a CEL. There were no symptoms like you described, it still ran great.

[forever_benz]

I have the same kind of problem with my W210 E220 diesel. If you keep the car on idle too long, there's a sudden jerk on the engine and the same happens when accelerating. It is as if there's a sudden power loss.

I had people tell me that there maybe dirt deposits in the fuel tank and lines. So I added the wurth fuel diesel additive to get rid of the deposits. It still didnt help. I also changed the diesel filter. Still didnt help.

And then a friend of mine said that this problem is common with most W210 E220's. Apparently its a problem with the injection pump. Any expert ideas as to how I could get rid of the problem please?

[Red66GT]

Think I found my problem. I believe I have un-metered air entering the intake. I went to take off my mass air meter in order to clean it and I noticed that there is a gap in between the intake and the hose that is after the meter. Is there a piece missing her or something?

[ohlord]

Maf should set into intake tube on both sides one to the air box and one to the intake tube. One end clipped one side clamped. make sure fully seated any unmetered air on the post maf side will give you the same off idle issue as I pointed out about the maf.
If you can't figure out why a gap is open that would allow air in,for the time being duct tape the gap. to prevent unmetered air getting in until you can look at some members engine and figure out what is missing or what you have installed improperly.

[Red66GT]

The problem area is the rubber hose that goes from the MAF (it's band clamped to the MAF) to the intake. There doesnt seem to be anything there to attach the rubber hose to the intake. Can someone snap a pic or something for me to show how it's supposed to attach? I'm stumped....... The duct tape is not a bad idea for a quick fix for now....

[ohlord]

it looks like the area involved is the rubber tube to the fixed firm intake tube that goes back to the intake inlet on the back of the engine. That area has a plastic slip ring that clamps over the incoming tube. Sometimes they crack,sometimes you can rotate it and slip it back on. When they crack is usually when people try to remove the tube to make getting at the rear most spark plugs easier instead of just working under the assembly. Hopefully someone will snap a picture for you as I am currently surrounded by my Mgb's and a W124 1994 320e wagon which will be on no help sending a picture of.

[Red66GT]

Of course....thank you ohlord (and others). Today I took off the top of the airbox (where the air filter resides) and took off the mas air sensor body as well. Then I only had to wrestle with the rubber hose to the plastic air intake. I had to remove the upper plemum cover as well, but was able to "snap"the hose cover back on.

So, basically my advice is to those who replace the air filter, make sure that you do not pop the hose off that is beyond the maf sensor. If you have idle problems after you change your air filter, check the hose after the maf.