Are the fuel gauges on these trucks notoriously inaccurate? My gauge seems to be pretty crazy below 1/2 tank and then I fill it up and it takes way less diesel to fill the tanks than I thought it would.

 

Define crazy a little more. Is the gauge erratic?

It is possible for the pick-up in the tank to break so when you get below 1/4 or so, the truck will run out of fuel because it can't pump any more. I have this issue with the rear tank on my truck, about an 1/8 of a tank and thats it. I found out the hard way.

 

Pickup cracking or falling off has ZERO impact on the gauge reading. Still something to watch out for, below aprx 1/4 tank.

But yes, the gauge, like most fuel gauges, is a VERY rough estimate. Front tank is 16 gallons short-bed, 19 gallons long bed. Rear tank is 18 gallons.

 

I understand that, just trying to get a grip on what its doing, the OP doesn't really say.

 

Sorry, to be more clear, it seems to drop faster when I am near and below 1/4 tank and that when the gauge appears to be near empty, I actually have more fuel than the gauge is indicating.

 

Pretty Normal ... on mine it takes a long time to go from full to 1/2 then drops quickly. When close to the red line the most fuel I can get in there is about 12-13 gallons. Think Ford didn't want users to run out of fuel so they designed it that way.