Fuel tank
 

I have developed a vacuum in my gas tank as the level goes down. I am also using more fuel.

did this occur after changing the tank or sending unit? If not, try replacing the fuel cap...older vehicles used vented caps that relieve pressure or vacuum.

Yes, you probably will need a vented gas cap.

Thanks, I'll give it a try. Would be a cheap fix.

Replaced the gas cap, no change. Do you think the float could be stuck? I've gone from 15 mpg to about 4.