OK, here's the problem with most of these. Make sure the sending unit in the gas tank has a ground. The factory used a 4 to 6" clip which spanned the length of rubber hose from the gas line to the sending unit. This should solve most of these problems. There is one other thing you can do. In the back of your fuel gauge in the dash, there is a small hole. Inside this hole you'll find a small gear looking adjustment. Put a screw driver in the opening and move the gear a little and your gas gauge will go up or down. One other thing to check, You might have a bad voltage limiter in the dash. Put a voltage meter on the output of the limiter. It should pulse from 0 to 5 volts.