The last time it happened was probably about a 1-1/2 years ago. By coincidence, I filled my 2000 ML 320 up on the same day my wife filled up her 1995 C 280. Although we both filled up with BP gas, we did not fill up at the same gas station. On both cars, the fuel gauge acted irregularly. We ran the tanks to near empty and fueled up with Exxon. After several tanks, both fuel gauges started acting normally again and have never done this since. We now use any type of gasoline EXCEPT BP (even the no-name brands).

After this occurrence, I had heard that when they remodeled the BP stations in Durham, NC (all stations were redone) they replaced the underground tanks and were having some problems with the material used in the construction of the nonmetallic tanks. This leads me to believe that the fuel gauge acting irregularly is tied to "dirty" gas. In my case, the fuel sending unit eventually cleaned itself up without any outside help.