Fuel guage suddenly reading 1/2 empty with a full tank

[BigE77']

Originally Posted by 87Bob

Guys what you may be seeing is the effect that sulfur in the fuel has on the resistor in the tank. Cheap gas is high in sulfur try adding techron to a few tanks and see if it clears up. Here is a copy of a post from a Corvette Forum where there have been a lot of these issues


#1 cause sulfur build up on the sending unit from using gas with insufficient detergent package....
Use a good fuel system cleaner like Techron fuel system cleaner ( NOT the injector cleaner) , Seafoam.
Berrymans Chemtool B-12, Valvoline Synpower fuel system cleaner for a coule tank fulls and switch to a top tier gasoline www.toptiergas.com

#2. corroded ground for the sending unit
#3. bad sending unit

I recently rebuilt the motor and the fuel guages worked prior to pulling the motor. After install they quit working, I must have pinced or moved a wire or something.....I have only been running 93 since the rebuild...Sometimes things show up at the stranges times though it could just be a coincedence, and be residual crud from previous cheap gas..im not leaving anything out of the equation