I have a unique problem with my W124 E 220, Fuel Tanks gets full exactly with 3/4 of its fuel capacity. Fuel gauge shows 3/4 full, but tank can't take anymore gas.

This started after leaving at local MB dealer to fix idle surge, looks like someone held air into the pipe running form charcoal filter as purge valve was full of charcoal bead's when I checked this weekend.

I just want to have some idea before leaving it back at the dealer...

Thank you