The gauge works off of a float arm in the gas tank, as well as resistance in the wiring. Normally, if the wiring is or shorted out, the gauge will show empty or full, and will not drop down (or move up) despite the amount of gas in the tank. You may want to try this, to check the wiring. Disconnect the connector for the fuel gauge sending unit, which is the left rear of the car by the tailight - the sending unit uses the yellow/red wire. Then jump the pin where the yellow/red wire is, on the gauge side of the wiring, to a ground, and see if the needle in the gauge goes to full. If it does, then your wiring is ok, and your problem most likely is that the float arm in the gas tank is not lifting as high as it should.
Yes when disconnected it drops to empty very slowly when I grounded it it went to 3/4 tank very slowly. Everything seems to work with the gauge other than its just off. a full tank shows 3/4 of a tank and when the gauge says empty I really have 3-5 gallon left. Any chance the gauge in the cluster is bad? And replaceable?
Actually, when the gas gauge is just on E, all of these gas tanks have about 3 gallons left in them. And the needle does rise or fall slowly, when working properly. Certainly, the fuel gauge itself can be bad, as well. If you disconnect the connector behind the dash where the yellow/red wire connects in (the 10 wire connector) and jump the yellow/red pin to ground, on the gauge side of the connector, you can check for resistance. If you have less than an infinite reading, you have a short to ground in the yellow/red wire between that connector and the gauge. If you get an infinite reading, and all your connections are good to the gauge, then the fuel gauge needs to be replaced.