Greetings,

New to the forum still learning to navigate. Hope this question is in the right spot.

I have a 2012 F150. About a year ago i had to replace my water pump. After doing so my check engine came on with an emissions reading. After some time I figured out I did mot connect a hose. This made the check engine light go away, but I am still having issues with gas reading.

-went from getting around 470 miles per tank to under 400
-guage will drop drastically. Can go from 300 miles left to empty within a ten mile span. Once i shut the truck down and let set for awhile it will go back to normal. , but then drops again.
-lot of pressure buildup on tank.
-hard to start when I fill up when it is close to empty.

I have check all hoses seem to be connected. I just replaced the purge valve.

Any ideas on what could be the issue?

Thanks in advance for the help