2006 Xterra SE fuel cap/gauge

I have an 06' Xterra SE and was hoping someone could help me out with a few questions...

I am experiencing a lot of gas pressure/buildup in the fuel tank; noticeable when removing the gas cap to refuel. I have to let this pressure escape the tank before I can pump gas. Is my cap defective?

Also, the fuel gauge shows less gas than I actually have in the tank. For example, I will fill up and the gauge shows a full tank... 50-75 miles later is rapidly drops to half way. Maybe the float in the tank is broken and sinks below the actual level of fuel-causing an incorrect reading? :thumbsdow errrr...

And lastly (the biggest inconvenience of all) is the time it takes to fill up... usually takes 20 minutes to fill up the tank (11 gallons of gas) as I am unable to set the fuel stream on the pump handle... half a gallon or so into fueling, the lever clicks off like the tank is full; leaving me to stand and hold the lever while filling-very slowly-to avoid any back flow... My guess is the position and angle of the fuel tube might be causing an excessive back splash inside the fuel tube... I dunno :runaround:

Any suggestions/help will be greatly appreciated... Thanks!