I've noticed that the fuel gauge on my recently acquired C250Td is very erratic to say the least. When you fill the tank, the needle does'nt move off full for a good 70-80 miles. However, once it does move it flies down. then sometimes it appears to stay at one level for 50 miles, and then suddently move about 1/8 tank within 10 miles ! Anybody else noticed this at all?