Why would fuel gauge go up and down. on 2005 Buick Rainier

The fuel gauge go's up and down at any giving time but fuel pump is working fine.

by in Slaughter, LA on May 06, 2013
1 answer 3 comments
ANSWER by on May 06, 2013
TEST GAUGE AND FUEL TANK SENDING UNIT.MOST LIKELY SENDEDR IN TANK
COMMENT by on May 06, 2013
Thanks is this easy to test and can we do this at home?
COMMENT by on May 06, 2013
IF YOU CAN DROP THE FUEL TANK OR HAVE A SCANNER
COMMENT by on May 06, 2013
Oh. No scanner.. thanks do you know about how much that cost.and one more? Do you know what would make the low beams go out for no apparent reason? High beams and fog fine.