Get a new sending unit from Ford. They are 18.00 Mine started doing the same thing. When I took the old one out, the whole core was loose, indicating it was getting ready to fail.
I have seen two blow apart. One was on a Jeep. The guy just built a brand new garage and it spewed 5L of oil all over the brand new floor. The other one was an Oldsmobile and it broke while driving. Unfortunately, this sensor was for the idiot light (no gage) and therefore the idiot light didn't work once the sensor blew apart. The lady fried the motor.
They are only plastic! 18.00 is cheaper than a new motor. Luckily, the car has a gage though, and you might catch it in time.