When my bonne gets to around a 1/4 tank of gas, the gauge seems to take a life of its own. It jumps all the way back to F, and sometimes dips back down to E, but usually stays around F all the time. Why is it doing this???

Here'* some information on erratic fuel gauges. See if any of this helps:

http://www.bonnevilleclub.com/forum/...ic.php?t=19491
http://www.bonnevilleclub.com/forum/...ic.php?t=18940
http://www.bonnevilleclub.com/forum/...ic.php?t=16093
http://www.bonnevilleclub.com/forum/...ic.php?t=16486

Thanks rand,

Theres some interesting stuff there that I hadnt seen before. I have used shell gas in the car a few times, and all the gas here is high in ethenol, so I wonder if that isnt screwing with my gauge.

For now I'll have to go by the trip odometer until I can better diagnose that problem.

Anyone have a part number and price for a sending unit for 1997 Bonneville. I have the same problem. Reads full all the time.
Thanks
Keystone

The last time I replaced a sending unit it was about $150 as I recall. It was not on a Pontiac (it was GM) but I think they are all pretty similar.

The sending unit is integral in the pump.

I have the exact opposite issue on my 99 and investigated this. It bounces around when it'* completely full. It doesn't resume normal operation until it reaches less than 7/8 of a tank.