Gauges going crazy

Sounds like the wiring harness connection in the back of the speedo cluster is loose. This will cause crazy reading and the vehicle will perform like normal... sound about right??

If your "goes crazy" means what I think it does, it's unlikely to be a float. That failure mode is "empty" all the time.
I'd say either sensor or wire between sensor and gauge.

I can only think of two possibilities:
1) The Ground Wire (goes from the sending unit in the fuel tank to the frame of the car) is not getting a good connection or
2) The fuel gauge in the dashboard is bad.

If your description means that the change in the gas gauge is random then check the ground wire. If you have a volt-ohm meter, try checking the resistance from the wire where it attaches to the sending unit, negative side. Remove wire from sending unit first. Make sure negative wire on V_O meter is connected to frame of car. Reading should be almost zero. Anything else and the wire you are testing does not have a good connection.
If your description means that you turn the car on and the gas gauge is reading full for awhile and then goes to empty, the gas gauge is bad.

jack it up, use jack stands. take off the front wheels, and go in through the wheel well to get to the spark plugs. Gas gauges on every blazer is freaking crazy. mine acts up when it`s at a 1/4 tank. Park up hill it shows more, park down hill, it shows empty.

To much trouble to replace, unless you have the time and money to replce the sending unit.

Mine does the same thing, the gauge is like a tachometer, it revs like crazy, but holds steady at high speed, it goes down to about 10 at idle, 35 at cruise speed and it will go up to 55 if I step on it. But remember it is just a pressure gauge, it will read this pressure with 1 qt of oil in there, so don't use it for a level indicator. Check the oil, and you know if it has oil in it. Hope this helps.

yep i do,,,you have a voltage reg on the back of the dash bord its gone potty,,,change it

That is the oil pressure gauge not the oil level gauge. Sometimes they can act that way when the oil is thin. When is the last time the oil was changed? Try using a heavier weight oil. When engines wear they require thicker oil. What size engine does you voyager have?

CLUSTER IS BAD, OR GUAGE FUSE IS LOOSE. CLUSTER CAN BE REPAIRED BY SOUTHERN AUTOTRONICS IN RICHMOND VA.

same thing happened to me, with a 2003 neon sxt..... but tranny went into error and wouldn't shift out of first til i reset the engine error, tranny and gages were fine (til it got cold). i had to warm the car up, reset the error to go anywhere. i was told it was the drivetrain computer. but i'm still checking other things.

Your dashboard circuit is probably burnt out. The same thing happened to me, it's like a $20 part but is about $60 with installation, check with a dealer though.