I have a '97 Monte Carlo that's doing weird things with the fuel gauge. This is a mechanical (not digital) gauge with a needle. When it gets down to about 1/4 tank, the needle starts jumping all over the place. For example, it will jump up to 1/2 tank, then back down to quarter, then way up to full and stay there until next time I start the car. Since I've never worked with IP's or the fuel tank, I was hoping someone out there might be able to point me in the right direction. My guess is a shorted wire somewhere...

Thanks in advance,
mchugh2001

 

Sounds to me as if the fuel gauge sending unit is bad/going out.. More bad news, it's located in the fuel tank and it's not cheap.....

My wifes truck does this and we have decided to live with it for now.

 

LOL ah the good ole days LOL My 78 did this for years .

two things to check on it
take the wires from the guade and ground one of the post, See what happens to the guage
If it gose to the bottom or top and stays more then likely it is fine

as far as the sending unit in the tank she be and they are fun to get to but not to bad after you get rid of the gas in there. Also a great time to have the tank cleaned out
take it to a radiator shop and have them boil and seal it works great and will give you a extra gal ( Kidding )

but the sending units are not a hard thing to change just drop the tank and take out the screw with lots of W-D40 oh did i mention LOTS OF W_D40?

once it is out it is a simpel plug and play deal plug the new on in and revers destructions


Also some thing to replace while your there is the float at the end of the sending unit Mine was the float it was so lose it would just bounce around and when the tank was full it had just enough weit it would sit pretty still after the tank got lower it would start to ride on top of the fule this is what they are suposed to do but after years of it doing this it had basicaly wore out the contact at certin poiunts and cused it to \send a fale reading so every time it did this the needel was trying to do its job and the tank was doing something completly diffrent

thin ya get the idea here

but it is one or the other .
Or the wires between most likely the sending unit gugaes dont go bad to offten.

 

my GTP did that just last month....luckily, i got the warranty so FREEBIE

it was the sending unit

 

I have a 2003 Monte ss the fuel gauge moves alot but mostly stays at full even though i know its not i was told to check the wires to see if its a bad connection is this a very hard thing to check out.

 

This post is 9 yrs old...
Probably would have been better to start a new post under repair help.

However...
You have a door in the trunk to check the fuel pump sending wires... maybe there just corroded/rusted or one has broken off...Check all the connections.
I'd start there..

Be sure to use some dielectric Grease when you plug it back in.

 

Thank you thought about posting it somewhere else just today when i looked at the whole thing closer and seen the dates but thank you for the info.

 

I have a 2003 Monte carlo and the gas gauge stays on emty and the low fuel is always on. Already changed the sending unit, what else to look for.

 

Well I'll be double dipped in doggy doo. Who would have thought a car manufacturer would do anything to make a car owners life easier.

My fuel gauge has been doing some screwy stuff lately, as well. I'll have to have a look for that door in the trunk.

Thanks for that info STUMPI.