Setting the guages back to normal

So in the middle of covering up my tire pressure light my gauge hands were fondled with. Now when I fill up I only show 3/4 tank and when stopped im doing -10. I tried filling up and setting the hands back to full and 0, but when I start the engine it goes back to 3/4's. How in the world I fix this.

 

Larger gas tank and no stopping

 

I like that would save on brakes atleast

 

maybe run the tank down till the little fuel lite comes on and put the gauge to the e mark? i changed the gauge faces on my mazda truck and had to take off all the needles.......6 of em to be exact. they just told me in directions to draw out the dash and mark where all needles were.......then when replacing them put em back where your drawings showed. it worked like they said. i should note that my mazda had a pin to stop the speedo at 0 . maybe try putting it at 10 mph and when ya turn it off itll go to 0 instead of -10. just a few suggestions. hope this helps.

 

I've tried setting them to compensate for what it's doing but it's like it has a memory and over time it miraculously goes back to 3/4. I heard that disconnecting the battery and touching the leads together resets the computer anyone know abou this.