I am heading out on the road tomorrow and when I got in the car to go and fill the tank I noticed that the gas gage did not work and was working before, what would be the first thing I should check. I am hopping it is not in the tank but let me know as soon a possible PLEASE!!!!
The sending unit in the fuel tank is notorious for failure. It's not overly difficult to deal with though, if that turns out to be the problem. However you probably don't want to pull it right now, if the tank is full.
The quickest check is to disconnect the plug off the sending unit and short the 2 wires in the plug together with a paper clip or piece of wire. With the key on, If the gauge goes to full, the problem is in the sending unit. If it dosent, its in the gauge or voltage regulator on the back of the dash. Sometimes the connection to the sending unit itself just needs cleaning.