Hey guys...ok, just picked up my son's first car. Has a number of small "issues" I will be working on over the next week or so..but ONE I absolutely can't stand and want to fix right away is Gas Gauge reading. Currently there is about 1/4 tank of gas in the car..yet the gas gauge reads from 1/2 to 3/4 full..the needle kind of floats between the two.

Is this the sending unit, or ???? how do I access it to replace? I have read there is some type of access door in the trunk for replacement??

Any help would be great. Thanks