1999 blazer fuel gauge

i have a 1999 chevy blazer and the fuel gauge wont stay still the needle bounces arourd all the time it it is in possible to tell how much gas u have what needs to be done to solve this problem please help

Could be a bad Level sensor on the fuel pump assembly, or could be a bad connection to the pump assembly (on top of the tank). Check the connector first, it's possible to have a build-up of crude inside the connector housing on later model units. ('98 and above pumps require dielectric goo on the connectors)

You can buy just the level sensor from a GM dealer for ~$100.00, or a complete new pump assembly which includes the sensor for ~400.00 + from any parts store, more for a GM unit.

The level sensor consist of a carbon coated scale fixed to the base of the pump housing, and the level float has a finger that slides against the wheel.
It's essentially is a resistor, controlling the amount of ohms sent to the dash gauge. Thus, as the level goes up and down, so does the gauge.

On my '97, when the sensor failed, it was because the carbon on the scale eroded.

It could also happen that the spring on the finger that puts force between the finger and scale is weak.

If you have to go with a new fuel pump and sending unit please do us all a favor and go OEM!!! Less worries trust me!