I have a 89 S10 Blazer, and my gas gauge seems to be extremely inacurate. One time I ran out with 2 bars of gas showing on the gauge. Just today i put in $15 and it hardly showing half a tank. I usually get close to full tank with that much, and the gas prices have not fluctiated at all up here where i live.
You probably have a bad sending unit.. I have the same truck and have not had that problem yet.. They are usally inside the gas tank..which means you need to drop the tank to replace it and I know that they aren't cheap either..
Just a thought...
Luvin 4 wheel'd life
1989 S-10 Shiny chrome
1999 Honda TRX400EX oh my