PONTIAC INSTRUMENT CLUSTER GAUGES FUEL LEVEL NOT WORKING

We Purchased A 1999 Grand Prix W/10100.00 Miles For Our Son's "first Car" And Within 2 Weeks The Fuel Gauge Has Become Erratic And The Power...

Gauge In Dash Not Working Right In Cold Weather Tach And Speedo Not Right And Now Fuel Gauge Reading Different From Time To Time In The Pass...

Are There Any Other Things That I Should Check In Regards Too My Fuel Gauge Not Working Before I Replace The Fuel Sending Unit?