I wonder if the fuel tank filter may have any influence on the tank float??
If the filter is dirty it may be blocking on and off.

Archive posts indicate that one can blow compressed air into a fuel line while gas tank filling cap is off.
This will clear up thae tank filter.

Good Luck!!

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD