10 liters at 30 km ! Help

hi,

In time for the Christmas party, of course, it is round again.

since yesterday the small loose 10 liter sprit needs 30 km. ( no city traffic) and he does smoke like a snake. otherwise it runs round, except for the empty run that humps. And he doesn't want to get really warm either.

can it be that the lamba probe is defective and it just goes too fat?

if yes, can I get a structural equivalent of unfit ?

Christmas greetings
W. Rising