Dash gas gauge stops showing proper gas level once it hits half a tank. Then gauge will fluctuate between empty (light will come on), full and anywhere in between but seems fine from full tank to half

SOURCE: fuel gauge changes the amount

The fuel sender is in the tank and is part of the fuel pump module ( all in one). the fuel sender is a rheostat and is like a dimmer switch in you home to dim lights, the higher the level of fuel the more voltage the computer sees hence the lower the fuel the lower the voltage it sees. With the age of the car this is likely the problem. But there is a part in the instrument cluster that reads this voltage and sends power to the gauge intermittently. In older cars it was called a anti slosh module. It was there because as the car went up and down a bumpy road the gauge would read erratically. the cost can be prohibitive to fix this but if you can live with it i would. If not expect to spend 600 dollars or more to trace it down and fix it.

Ronny Bennett Sr.

• 6988 Answers
• Posted on Oct 14, 2009

SOURCE: Fuel gauge not give proper reading.. register full

Sorry to say,but the fuel sending unit is the problem,the fuel tank will have to be lowered out of the vehicle to replace the unit.If the fuel sending unit is not available by itself you will have to replace the whole fuel pump assembley.

SOURCE: gas gauge shows empty after filling gas tank

The gauge circuit is shunted on most cars, this is wierd, but needed to stabilize the readings... Your description sounds like normal function. Drivers would complain if the qauge were to be instant, going around corners, starting, stopping, all move fuel, and the gauge would indicate this, cauing driver alarm...Been this way for ever, although yours sounds like it is on the far side of the scale...if it reads correctly after a while, you could replace everything and you would have the same performance.