This sounds really unlikely to me.

Maybe the problem is caused by water in the tank?

Rob

Your car should have the later style of VDO fuel level sender with a small
3-pin connector that is seperate from the fuel pump power feed wiring. When
I first got my 1985 900i it's fuel sender was completely dismembered inside
the tank and the only part left in place was the top and 5 percent of the
steel rod that the float slides along. The rod had broken where the threaded
section right at the top stopped, so the whole body of the sender, plus the
float, had fallen to the bottom of the tank. 8-)

Used level senders are not hard to find - just borrow one from a wrecked
1983 or later classic 900. Providing you don't get the white plastic bodied
sender (used up to about 1982), you can do a direct replacement as far as I
know. Saab had a retro-fit kit to upgrade from the old type sender so I
don't know if that was a factory recall type mod or something optional.

Or you can get them from sellers on Ebay fairly often.

Well the metal rod, etc. won't float. I used a pair of long kitchen tongs to
fish around through the fuel sender hole in the top of the tank to find some
of the parts of the old sender and the float is still in there somewhere.

If you want to remove the fuel pump out of the tank you'll get a much larger
hole to get into the tank through, but you might create more work if you
find the fuel pump pickup is breaking down as well (however it could explain
some of the problems if the pick-up is falling apart or it's blocked
somehow).

Regards,

Craig.