On my twin tank F350 when it gets down to 1/4 of a tank both front and rear tanks seem to be empty. The reason I think it is empty is that the engine stalls from lack of fuel. I switch tanks and wait until the filter fills up and it will start on the other tank. When I go to the service station both tanks will only take 12 gallons. It has done this 3 times so I know how to fix it by just switching tanks. What I do not understand is that the tanks should hold over 18 gallons each. Where should someone look to correct this. It is a 1993 crew`cab 7.3 diesel. Thank you

 

The plastic pickups on the senders have broken, pretty common. You can replace them or use some hose, with a V notch in it, to extend the pickups. You'll either need to pull the tanks or lift the bed (easier).

 

curbill2,
Welcome to FTE and the IDI diesel forum.

GenLightening has nailed the problem.

This has been very common on the 80's trucks for a while.
The 90's models are getting to that age now.