And the car is about 6 days out of warranty?

Well, this is your first lesson in M-B dealer repairs. It's time to call
an independent shop.

In the US Federal law requires the OEM's to maintain a supply of service
parts for (I think) 10 years.  Go slap the dealer, he's a $^^$&# LIAR!!

Davehd

Paul:

The early ML's, MY1998 through early MY2000, had known problems with the
fuel pump.  The most benign symptoms were an erratic fuel gauge and the
worst were complete failure of the pump, this leaving you stranded.  The
fuel pump in your MY2001 is the 2nd generation, which is generally not
subject to those failures.  However, there were some general problems with
insufficient fuel delivery (mainly on the V8 models), so a 3rd generation
pump was created.  This newer pump does require larger fuel lines and a
larger filter and is now the only part available, which does in fact mean
that if you need a new fuel pump, you will have to have all this work
performed.

Now, my question to you is, what is the symptoms of your fuel gauge failure?
If it is that it stays on empty, then I may have a solution for you.  I had
a problem with mine where I would fill the tank, but the gauge would not go
to 1/1.  Instead it would stay at the pre-filled level, and even continue to
drop as I drove, almost as if I had not filled the tank at all.  Sometimes
it would fix itself after some driving and a few restarts, other times it
would fix itself after a few refillings of the tank.  While my truck was
under warranty, the dealer replaced the instrument cluster and installed the
3rd generation fuel pump along with the necessary upgrades.  Unfortunately,
it did not correct the problem.

One day, I got the bright idea to "reboot" the fuel sender.  This is done by
disconnecting its wiring harness (which is easily accessible on the frame,
at the driver's side rear wheel).  Turn the ignition switch to position 2,
but do not start the engine.  With the ignition on, disconnect the wiring
harness, wait a moment, the reconnect it.  In all cases, my fuel gauge
returned to normal operation.  What I have discovered is that there is a
"fuzzy logic" circuit in the system that is used to damped variances in fuel
level due to the shape of the tank and motion of the fuel when the vehicle
is moving.  Apparently, this logic is sometimes confused after a large
change in fuel levels and this "reboot" process just resets its starting
point so that it will work again.

There is a setting that can be changed in the AAM that will disable this
fuel gauge dampening, but there are trade-offs in doing that.  One thing
this setting will cause are gauge fluctuations as you drive.  Also the gauge
will not accurately show the volume of fuel; instead it will show the
"level".  Since the tank is not perfectly rectangular, there is a greater
volume in the first 1/2 of the tank than the bottom 1/2.  My gauge is
extremely accurate in that I can drive as many miles on the last 1/4 as I
did in the first 1/4.  So far, I've had to reset the circuit about five
times over the last few years so it's not a big deal.  Also, I have noticed
that it is more of a problem when I fill the tank very full from a very
empty state.   I have gotten to where I refuel just below 1/2 a tank and
that seems to help.