I thought it could be the fuel cap, but it was replaced with a new MB cap at the last smog inspection a year ago, so I ruled it out. However, it is cheap enough that I will get a new one and see if that makes it go away. If it does turn out to be the cap, then either MB quality has dropped for the cap to last less than a year, or more likely, the leapord urine that is sold as EPA approved gasoline in southern California did a job on the seal!!!
2003 Firemist Red/grey leather SL 500
2015 Palladium Silver/black mbtex GLK 350
1987 Smoke Silver/burgundy mbtex 300E Sportline (SOLD)
Click to see 87 300E