Hi Folks. I have a nice 1985 Deville. Last summer I dropped the gas tank, cleaned it, sealed it and put back into the car. The tank is ok now but my gas gauge is crazy. When I have used about seven of the sixteen gallons of gas, the gage goes very quickly from nine gallons left in the tank to 8,7,6... to E and the car stalls. I fill it up and it takes only seven gallons. Am I supposed to reset something in the ECM or do I have a mechnical problem in the tank? Thanks.