Im having the same problem my gas gauge will only go up a little bit on my 69 1/2 Maverick I tried to fix it multiple times but to no avail. I'm thinking the ground is bad, so thanks Diddie I'm going to try that, but if it is the fuel sending unit is there a way to cure the problem without getting a new fuel sending unit because with my original gas tank I got a reproduction one for my year, so should I cut my losses and just get a fuel cell in the back of the trunk?