Fuel gage moves eratically while driving. 95' GP

[mchill07]

While driving around usually under a full tank, the fuel gauge needle moves all over the the place but is accurate for the most part.

It is really annoying. Sometimes I will go from 1/2 down to 1/4 then all the way up to 3/4 before settling back around 1/2 tank. happens during stops starts turns and curves.

Is this a sign of something to come, or just the way it is?

[Schurkey]

While driving around usually under a full tank, the fuel gauge needle moves all over the the place but is accurate for the most part.

It is really annoying. Sometimes I will go from 1/2 down to 1/4 then all the way up to 3/4 before settling back around 1/2 tank. happens during stops starts turns and curves.

Is this a sign of something to come, or just the way it is?

1. Missing/broken baffle in gas tank?

 

2. I am reasonably sure that as part of the circuit board--at least on some older vehicles--there's an electric "damping" mechanism on the gas gauge that slows the needle response. I'd have to look up how it was supposed to work--I've never dicked with it. Might be worth looking through the service manual, and if there's some kind of damper, pull the cluster and look for broken circuit traces or defective solder joints.

[RobertISaar]

i've seen VERY few late 1st gen and all 1.5 gens with a smooth fuel guage at anything other than almost full or almost empty...

 

the tank on the MC was replaced in ~2005(rusted through at the pinch/weld seams) and i remember it still being wonky even right after it was done.

 

i'm fairly certain it is the dampening circuit, on the earlier clusters it's just a simple resistor/capacitor combo and works quite well. when i did pull the cluster out of the MC the last time, i remember seeing a similar arrangement, but for some reason i didn't attempt to correct it? the capacitor used is an electrolytic unit, 470uF, 25V ratings IIRC. if i had to guess, i'd say it's worn out. then again, maybe i have an isolated case.... this cluster is all kinds of intermittent when ambient temps get to ~80*F or so.

[urbex]

Yeah, I know mine is WAAAAY off, and it'll drop considerably on right turns and when I slow down especially when getting off of the expressway.

[mchill07]

This "dampening circuit" Is something already installed on the cluster that should be visible when pulled out?

[Dark Ride]

My Lumina has always done this, I guess it just never bothered me enough to do anything about it.

[mchill07]

I removed the instrument cluster, which was difficult to maneuver out, and the only resistors and capacitors I saw were soldered on the PC board. not sure if im gonna pursue the matter further as the gauge is working.

[Euro]

I think it's just one of those things a W-body does My Lumina did it whenever it was below 1/2 tank.

[alec_b]

Def. a common issue. Both my '95 GP and '96 MC did this. Fuel gauges were all over the place on turns.

 

Oddly enough, my '91 Regal never did it. With either the analog cluster or the digital cluster I swapped in.

 

My Caprice did is too, but not as bad as the W-body cars did. So who knows.

[jake91]

My cutlass did it under 1/2 not real bad but on occasion I saw it go all the way to empty from 1/3 on a hard stop or corner lol

[rich17]

I think its just a GM thing. My car does it as well and it has a new tank and sending unit in it.

[mchill07]

My 89' cs and both of my 93's moved a lot less, really only noticeable on xway ramps. This 95' GP is all over the place, my guess is that there was a change in the components that they used in making the instrument clusters. It's just something I noticed with my newer w-body.

[virtuetovice]

My 89 Cutlass is 1/4 tank off, sometimes more sometimes less. I top it off every 150 miles and don't sweat it because I don't wanna eff with it.