I am the owner of vintage enterprises, which is a muscle car restoration shop and also buy and sell nice original parts. I have a 2002 Avalanche 2500 and a 1996 3500 silverado dually. The 1996 3500 has an oil pressure gauge and a fuel gauge that is spiked well beyond the numbers. I replaced the oil pressure sending unit and also the gas tank making sure the gas tank was properly grounded. Does anyone know what the problem is?