Hi, I'm new here I hope i'm posting this in the right place.
About 6 wks ago I almost ran out of gas, a warning light came on and said I had 4 miles to go, when I got to a station it was down to 3. My truck is a 2010 F150 XLT and it doesn't have a gas cap, has a flap that opens when the nozzle in inserted. When I inserted the nozzle it sounded as if I released a vacuum. I tried to fill it up but it only took 20 gallons and it holds 26. The gauge read 3/4, I thought it had just knocked off early, but since then I can't get more than 3/4 of a tank, I've tried rocking the truck to get it to take more thinking it might be an air lock but it didn't work. I have tried to fill it 3 or 4 times since and it will not fill up.
Anyone have any ideas or have dealt with this before?

 

Check your vent line, it sounds like it's clogged.

 

Crawl underneath and make sure the tank isn't partially collapsed.

 

Since you drove it until there little gas left, my vote goes to a damaged fuel gauge sending unit. If drive over any rough bumps, even once, while the tank is low you can bend the shaft that the float is on. Usually they end up showing less gas than is actually in the tank....a full tank might show 3/4 on the gauge. Been there done this with several F Series over the years including the last 2004.

 

Thanks for the replies. I don't think it could be the gauge because of the about of gas it took the first time. I got up under the truck and I couldn't see any sign of collapsing of the tank, of course I couldn't see the top. I don't know how to check the vent, could someone tell me how?

 

Hmmm... I have seen this issue...

I just pull the nozzle out slightly (about 1" or more), and it should fill the tank up just right. Those pump handles detect the flow of air, when the air stops a mechanism inside the handle trips thus cutting off the gas.

Only happens on a few gas pumps though.

When you try it, you can see when you are full by keeping the key in the "On" position, but not keep the engine running. Keeping the engine running while filling is a big no no.