The gauge on the 280SEL sometimes does the wiggle thing, and I too simply used the trip meter for an accurate guage of when to fill. Now however, the odometer/tripmeter has decided to stop working all together, so I am now guestimating everything from miles driven to MPG to "I wonder if it's time for gas"
This weekends project is - pull the cluster and get the speedo head ready to ship off for repair.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.