The latch for the gas tank will not pull up. Won't even budge.

Its likely rust on the lever or pivot.
Start by opening the tab on the fuel door release cover (5). A small flat screw driver will do the trick be gentle its plastic. Remove the phillps screw then wiggle the cover off to the side. Now inspect the lever and pivot pin for rust. Try some WD40 or similar lubricant and let it soak in for a couple of mins. When trying to free up the stuck lever you need to pry/lift by the metal part and not just on the plastic as its going to break with too much force. In the worst cases you can remove the entire lever and bracket from the floor and use heat to free up the lever. This is done by removing the door sill trim then lifting up the carpet. Now you can access the floor mounting points for the lever. With the nuts on the mount removed you should be able to slide the cable out of the slot in the lever arm. Be careful when heating so you don't melt the handle.