Fuel guage needle moving crazy jumping side to side?

1999 CHEVROLET SUBURBAN
238,700 MILES • V8 • 4WD • AUTOMATIC
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HELLOHIWELCOME
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  • 21 POSTS
The fuel gauge needle is jumping side to side. The fuel pump is new. I replaced the old one in 05/2011. When I'm driving, the fuel gauge jumps from "from full to empty to half gallon mark to full to 1/4 gallon mark to empty etc and so on", so is not giving me an accurate reading. It gives me a false reading so I don't know how many gallons I have. I know it's not the float (hope not) maybe an electrical issue. Need help! Thanks alot!
Oct 10, 2012 at 11:58 PM
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MHPAUTOS
  • ✓Experienced Mechanic
  • 31,937 POSTS
I would be suspecting the tank sender unit, the gauge will not move about on its own like that, i would get the sender out of the tank and tested first.
Oct 11, 2012 at 1:15 AM
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DMCCRACK
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  • 8 POSTS
Mine does the same thing. Not wildly, but like a constant, very fast shaking side to side - the actual distance it moves is slight. The pump bit the dust so I replaced the whole assembly (including the sender). The fuel gauge still does the same thing.
Oct 12, 2012 at 8:57 AM
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DMCCRACK
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  • 8 POSTS
I haven't checked mine, but there is a frame ground back there by the tank. I doubt it is the problem, but it wouldn't cost anything to make sure that connection is good!
Oct 12, 2012 at 8:59 AM
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