"anyone else ever have this problem?"

Someone has, but I have not. And I'd have to think that problem would be extremely rare in a car except as one caused by the technician, i.e. a "bad" part.

But I could imagine many ways a person could cause the fuel gauge to be stuck full. If I list them, you could come back and say no to them, and then I could imagine some more...

1) Float arm hung up on sender.
2) Pump and sender wires (black, gray) swapped at connector.
3) Gray wire pinched.

What year 240? Wagon or sedan?

Test the sender with your ohmmeter after installation. Simply measure the resistance between the gray wire (disconnected from the harness of course) and ground. Here's a real chart showing the resistance reading you should expect. Prove the sender is sending truth before getting lost in the cluster. Pursue the temperature trouble separately. The stabilizer is not a mysterious thing, it works just like Don describes, with no more than 13.8/10 influence factor.




--
Art Benstein near Baltimore

Thieves who steal corn from a garden could be charged with stalking.