Joe - do a search on "fuel sending unit" or "dancing fuel gauge". TONS of info on this subject.

I even contacted VDO about the gauge on the cluster. It's a very common problem with MBs. Sometimes it is a dirty or failed fuel sending unit. It can also be a cracked cold solder joint on the gauge itself (at the dash). Remedies include cleaning or replacing the sending unit, pulling the instrument cluster and re-soldering the fuel gauge solder joints or simply replacing the instrument cluster (very expensive).

Since your gauge is not jumping around, I would guess it is a stuck/dirty sending unit. Good luck!

__________________
Chris
2007 E550 4Matic - 61,000 Km - Iridium Silver, black leather, Sport package, Premium 2 package
2007 GL450 4Matic - 62,000 Km - Obsidian Black Metallic, black leather, all options
1998 E430 - sold
1989 300E - 333,000 Km - sold
1977 280E - sold
1971 250 - retired

"And a frign hat. They gave me a hat at the annual benefits meeting. I said. how does this benefit me. I dont have anything from the company.. So they gave me a hat." - TheDon