Lousy mpg '94 E420 - Causes?
 

I've been getting lousy mileage on my E420 lately. Well, at least since I've replace the ETA (wires toast) and a few weeks later the MAF (voltage code).
I'm guesstimating 15mpg, if I'm lucky. No codes, except for an upshift delay code a few weeks ago - hasn't returned since clearing it.
Until the wiring shorted out in the old ETA, I could get 23-24mpg.
Did I get a bum rebuilt unit? (4mercedes) or is this just a coincidence, and I need to look elsewhere?

Thanks!

Whats it supposed to be getting?

Mercedes are know to get crappy gas mileage but you could clean ouf some of the parts in the fuel system such as the injectors and other devices.

If I had dirty injectors, I would think that I would have a rough running engine - I do not. It is getting close to cap and rotor replacement time, but not so much to explain the poor mpg that I am getting. I used about 1/2 tank for roughly 100 miles.

You might pull the plugs and see what they look like - could be a clue there.

Poor gas mileage
 

Larry, change your spark plug. Stick with Bosch Spark Plug FR8DC. Also consider changing your air filter, fuel filter and run some fuel injector cleaner.

E420 mileage
 

Larry,
I have the same car. I average about 22-23 mpg on trips but it falls to 14-15 around town with the AC. I don't think you will do any better with the V-8. And you need to test using multiple tanks of fuel, not just one.
Anziani

87 300E 200K
95 E420 108K

I too have the same car and get 27-28 on the highway and 20 in the city.

Huh ?
You better quit smoking the " good stuff ".
My Mercedes ( V-6 ) gets better gas mileage, than my VW ( 4 cylinder ) ever did. ;)