You could try the Goe Method on that tank and see if the Calgon makes it slippery inside and cleans the gunk off of it. You can google geo method and it will come up.
What it is you use 2 gallons of warm water and add 2 cups of Calgon to itand then 1 cup of powedered laundry soap. Dump it in the tank, Id then add 5 or more gallons of water to it, take it for a drive and drain and see if that cleans the sensor.
Brian, Tamara, Abigail
2003 Lincoln Navigator Ultimate Edition 4X4
2004 Crossroads Cruiser CT30RL