1995 C220, I just bought 4 gallons of gasoline and my gas gauge would not register it. The reserve light stayed on the 6 miles I drove home. I drove home thinking the station had ripped me off for some gasoline and when I went to drive back to the station a half hour after I got home and the gauge corrected itself and went up to 1/3 tank where I expected it to go. Not sure what is wrong here. Looking at the system there are two tanks and two sensors. Could this be a balance line between the two tanks issue or one or both sensors? Not sure where to start here? Has anyone seen this problem before? Thanks John