Ill Running 1995 S 420

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03-20-2016, 01:56 PM

mayolives

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Join Date: Jul 2015

Posts: 2

Ill Running 1995 S 420

I've been trying to repair my ill running 1995 S420 for about a year now and need some good advice. At first my problem was intermittent, then gradually became a full time nuisance that ended with my very nice, low mileage car not even starting. Long story short, this began with hesitations when accelerating and at times would "pop" back through the throttle body as if the engine was out of time. But I could "peddle" the accelerator, just like it was running out of gas, until it would gradually pick up RPMs. Engine diagnostic test would show nothing. Below is a list of parts that I have replaced. All were new OEM Mercedes parts. After last replacing the main wiring harness, it will start but runs very poorly, and just like I have previously tried to describe it's condition. I'm really stumped and my next attempt is to replace the throttle body but need and explanation of a few parts that must be associated with the throttle body. Could someone explain the throttle potentiometer, air flow meter, butterfly servo. Are they part of the throttle body? Is the air mass sensor part of it also? Thank you in advance for your thoughts and help. Here is a list of what I've replaced to date and there may be something I forgot due to all this being strung out over the past year.
NEW OEM PARTS INSTALLED
cleaned fuel tank
fuel filter
spark plugs
ignition wires
rotors
caps
cap seal rings, cable plugs, suppressors
ignition switch
air filter
serpentine belt
crank position sensor
intake manifold gasket
checked fuel pressure
sent ECU to be checked.....all is well
vacuum pump for door closures
door lock pump