i just bought my first chevy blazer. a 2003 4dr 4x4. when i test drove it the low fuel light was on and the guy said it was fine for the test drive. so, after i bought it i added 20$ worth to get home and it moved up fine. the after a couple days of around town stuff the gauge was on empty so i went to get gas and he was only able to add like 2$ worth and he showed me it was full at the filler. the gauge still shows empty and the low fuel light goes on sometimes sometimes not.

 

any ideas?

 

The roll-over valve is probably stuck not allowing fuel in the tank. You can try smacking the lower end of the steel filler neck, (just behind the driver rear tire) with a mallet and the ball might free up. If not, remove the neck and see what's going on with the ball.

 

i had just assumed it was the gauge being wrong. ill have to check the tube in the morning. i was driving around all day thinking the gauge was wrong. yikes good thing i didnt run out of gas. i guess i can tap the gas tank and see how empty or full it is.

 

If smacking the filler neck doesn't help, (gotta be down at the lower end of the filler where it connects to the rubber hose) straighten out a metal coat hanger and feed it down the neck, (you'll feel the ball) and bump it a few times.

 

Could be a fuel sending unit if tank is full and shows empty, sulfur buildup on sending unit can make for false readings. If it is full of gas and not empty, try some Chevron Techron Concentrate Plus from Autozone or Advance auto parts, it will help dissolve the sulfur buildup on sending unit. I have had this help with my blazer and my Vette when gas gauge was going haywire.

May take a couple bottles, one at a time per tank of gas of course

I never heard of the ball in the gas tank, mine has a small check valve on top of gas tank, connected with vacuum lines to shut off pump if gas gets in it when rolled over, I've had my tank off and never saw the ball, I will look for it next time though, if it is there.