"Bouncing" fuel guage.

My fuel guage "bounces" in my 99 Blazer. When it is full, it is fine but for example when it gets to 1/4, it will bounce up, and down, even when sitting still. Any ideas?

Your fuel sensor in your tank is bad. If your's is like my ZR2 (S10 4X4) it is built in with the fuel pump. It's cost here is 287 plus tax. I chose not to replace mine. I get 20.8 miles to the gallon. I just keep track of the miles.
SC

Your fuel sensor in your tank is bad.
SC

If you have the original pump in the tank, you can get the fuel level sensor from any GM dealer. They are OEM parts, and are only available thru GM. If you have an aftermarket pump, you'll need to buy a new pump assembly.

For the original GM pump,For a 2 door, the sensor p/n is 25314231, For a 4 door, the p/n is 25314258. The difference between the 2 dr and 4dr is the length of the arm.
Each unit is priced at $128.38 list. I got mine from www.gmpartsdirect.com for $79.00. Took a week to get it.

You'll have to drop the tank and remove the pump assembly to get at it, and be carefull not to break any of the plactic feed,return, and vent lines on the top of the tank-the lines are short and hard to get at. The feed and return are pinch connectors, the vent is a pry-off type fitting.

Here's a link to my post on replacing the unit. Hopefully it'll help you. Eventually I ended up dropping the tank 2 more times and replacing two fuel pump assemblies.
http://www.automotiveforums.com/vbulletin/showthread.php?t=368013&highlight=fuel+level+sensor

HI, Just a quick clarification first.
If you stop and leave the vehicle still for a little while does the guage stop moving or does it still "flicker"?

If it still flickers you have a bad electrical connection somewhere in the system, More than likely its in the fuel tank sender. However if you just notice the excessive movement while driving around its more than likely the Slush Valve. Its essentially a small Eletrical component that retarts the reaction of the fuel guage to the needle on the dash.

In the blazer I am pretty sure its integrated into the fuel level sensor at least thats the way it looks according to the service manual. In Canada the fuel level sensor is going to run you $197 at the dealer.

HTH
J

It "flicks" even while sitting still for a few minutes. It sits perfectly still when full. It seems that I can judge how much gas is in there by where the needle spends most of it's time. I don't drive the vehicle, my wife does. Maybe I should drive it for a day or two and see how it works.

In Canada the fuel level sensor is going to run you $197 at the dealer.

HTH
J

Really that much? Isn't the exchange rate at ~20%

Is there a Canuck gmpartsdirect ? wholesale seller?