I have an '02 Avalanche I replaced the fuel pump and all was well until my fuel gauge one day after filling the tank shot from full to empty and the low fuel light came on. After driving a while it went back to full but now it is random it will go from full to what looks like the correct reading the back to empty and the low fuel light comes on. Any suggestions??

 

First thing I would do is double check the electrical connections on the top of the tank and also make sure the ground straps got put back in place after the tank was put back in place.

 

Thanks Il'll give it try, just sucks droping the tank agian.

 

If the connections are good you probably have a bad stepper motor in the cluster. Very common on the 99-05 trucks. There are a few repair guys that advertise on eBay and will replace all the motors (each gauge has one) for around $100. Good luck.

 

There should be some changes should be done in the fuel gauge.

 

mine will flicker to show the correct amount of fuel on my gauge when i start my truck ( 02 avalanche 8.1) but then it will shoot right back down to empty.. there is currently 1/2 a tank of gas in it right now but it still wont register.. ive checked the fuse and the relay with no luck still.. checked to see of it was the gauge but didn't see any problems!!! could it be the fuel pump?? what shoulg i do????