My 1999 GMC Sierra 1500 has an intermittent gearshift indicator light on or black problem. We have checked and cleaned the ground points. Also, the gas gauge is inconsistent...even when the tanked is just filled, the gauge falls to empty, then eventually will come back to the amount existing in the tank. Any suggestions would be greatly appreciated!

It would be nice to get a little more detail on the intermittent light - you say "intermittent gearshift indicator light on or black problem" - Would it be ok if you elaborate a little more? Thanks.

As for your fuel gauge - you will be needing a new sender unit. Someone liked to keep the tank full all the time, so the wiper that moves across carbon strips wore them out just on that part. Thats why when your fuel quantity goes down, the wiper moves down to a good part of the sender board.

Ford is real proud of that sender unit - $140.

You can buy one on eBay for about $80 shipped to your door --