slow throttle response like your describing and missing when accelerating. That's what I would be looking at with no codes. I think it is most certainly fuel

The fuel rail has a pressure test port.
With a gauge , you can test both holding and running pressures,
[ this also test regulator] ,but with your condition, you also want to check Volume...
That is where a filter will fool you....you can still have proper running pressures , but when under a load, volume can be too low for demand....

to add to what Arthur said, I would bet money it's a partially clogged fuel filter

Here is what you are looking for :

At idle, 3.2-3.6 Bar [ bar =14.5psi]

W/vac line to reg disconnected , it should rise to 3.7-4.2

It should hold for 30 min after turned off to no less than 2.5 bar

Volume should be 1 liter in <35 sec.

I would imagine your guy has already done a FP test, but you may want to ask...

I agree with JoeP. have the values checked for the self adaptation and air mass.If you're hitting on all cylinders but slow to rev,probably it's the airmass sensor.On these cars that IS part of starting with the basics.
Paul

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Paul Roberts
Mercedes Centrum Inc.
Bellevue,WA.

I tend to agree with the others that your problem is likely fuel supply related.

However (comma space) I had an intermittent problem very similar to yours, and it ended up being one bad coil wire causing the problem.

Go figure.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

UPDATE....

1) VIBRATION

thanks for all the responses. i have changed the flex disc and the tranny mount.
this definately resolved most of the vibration problems.

2) HESITATION UNDER LOAD.

i have replaced the fuel filter..... no change.
checked fuel pressures...all o.k
(not sure how to check for flow..volume) i guess i have to bridge fuel pump somehow??????

the car still hesitates under full acceleration or when kicking down hard...

how do i check "for self adaptation and air mass for mass flow sensor" do i need special equipment or can i do the check???

your responses are appreciated and it is taking "baby steps" but the car is getting better.....thanks

()

any comments please?
i am desperate to find how to check values as described earlier.
althouhg i replaced the coils and coil connectors i only replaced the other 3 plug leads today......no difference???

Spikes, type multimeter in the search and you will find a lot of usefull information. Also search for Led/sw. For a 97 E320, I am not sure if you can check the various modules, with the information you will find with the above searches.

I would focus on the engine control module, this module controls most of the engine functions, including air fuel mixture for various operating temperatures.

Also, these car have a whole bunch of vaccum line, I would make sure everything is connected.

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Zafar
94 E320 58000 Miles

cant find much help under search.
what causes car to hesitate and not run when under kick down load......

is there anything else i can check..?

any one?

have you checked for codes yet? I see no where that you've done this. It would help you and everyone else to better troubleshoot your problem. Aside from gathering any codes that have been tripped we are all guessing from prior experience, and that could end up being very costly for you. It's called the shotgun theory, if you throw enough parts at it you'll probably end up fixing it sooner or later, and that's what you don't want!!

Please either check for codes yourself of have it done at a shop.

Dale is right. You're wasting alot of time throwing parts in that you may not need.Spend some money and have a shop plug in and retrieve complete engine data.You can have a part malfuntion without the check engine light on.Like I mentioned before,my money is on the mass air sensor.
Paul

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Paul Roberts
Mercedes Centrum Inc.
Bellevue,WA.

thanks paul and jetforman.

i was under the impression that once the battery had been disconnected and no check engine light there are NO CODES.

i will get a shop to pull codes.

thanks guys........it is dissapointing when parts are replaced and does not fix the problem