gas gauge erratic at best

**jkstewart1** · 10-11-2007, 10:26 PM

The gas gauge on my 99 goes down to half a tank if it goes down that far, then starts going back up again. I'm just filling up when I get to 500 miles on the trip odometer. Is there a fix for this without dropping the tank?

Any suggestions?

Thanks,

John

**Cableguy** · 10-11-2007, 10:28 PM

Either fuel pump itself or grounding issue at tank. You'll probably have to drop it. Sorry. Good luck

**jkstewart1** · 10-11-2007, 10:30 PM

Thanks for the quick reply. It runs fine. Just an annoyance really, but I figured if I could fix it without too much effort, then why not?

**Cableguy** · 10-11-2007, 10:47 PM

Its seems to be a popular prob with 99 trucks in general for GM. My 99 Savanna flickers but I've seen the symtoms like yours on one of our other Savannas and tank had to come down to get at ground strap. People have posted here with same probs before(From Suburban to C/K)...I know that sucks.

**GaryL** · 10-12-2007, 10:08 AM

Mine started acting erratic just before the fuel pump quit. It's not to hard of a job on the 99's as long as the tank isn't full.

**95CTburb19** · 10-12-2007, 02:31 PM

mine used to do that (99 old body style sierra) now it just sits on full all day long.

**nowlaj** · 10-12-2007, 05:43 PM

My 00 Safari had that problem. It was the Fuel Pump / Sending unit. It was located in the gas tank.

**unplugged** · 10-13-2007, 01:07 AM

The bounce in mine is more pronounced near 1/4 tank. I try not to let it get that low so I don't run dry! An erratic gauge isn't so bad when you have a 42 gallon tank.

**skivhere** · 10-13-2007, 02:05 PM

My 96 did it when I first bought it, found out it had been doing it since it was new...he was just too damn lazy to check it out. I also had an erratic speedometer...actually reminded me of the old days when you would have to lube the speedo cable...it would jump around sometimes, or just plain not work. Found out from a GM tech buddy of mine that it wasn't too common of a problem, but it did happen on some of the trucks. Turns out the gauge went bad, no ground or fuel pump problem. I replaced my cluster and it has worked fine ever since.

Not saying that would solve your problem, but that's exactly what mine was doing, and it solved it.