i don't know if this is normal but my gas gage on my 1988 350 tpi iroc z is suppose to be what they call a floating tank when the car is full it is fine but when the car get off full if i hit the brakes it goes down below half then if i hit the gas it comes back up and i can never really tell if i am really low on gas the needle floats around so bad.i never seen a gas gage do that most needles don't move very quickly.but if thats normal let me know.

 

Mine floats quite a bit as well... I know I'm not a Z, but I sympathise with you... As far as I know the way the tank is shaped it causes this problem, I'm pretty sure it's normal...

To get a correct reading, take the readings from when you are crusing on a totally flat (or as close to flat as possible) surface... that'll give you a ball park... If the car starts to die on accelerated hard turns, you know you don't have very far to go before you run out...

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Mine does it too. Sometimes it can vary as much as 1/2 a tank!

 

mine too

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This is a fairly common problem called floating needles. They are now 'floating' giving you an estimate of how much gas you have.

Don't feel so bad, my tach also floats when I floor it, and my battery and temp guages are dead.

The only way I know to fix is to re-calibrate them individually. It's a pain in the ***, the gas one is simpelest though... fill your tank and then take the needle off and put it back on at the full position.

This happens to people who whiteface their guages a lot.

Anyone know a better/easier way PLEASE email me.

Jm

 

That's what it's supposed to do. Don't worry about it. When it stops moving, it's time to put gas in. If you see it move, you still have some. It's not so hard. Of course, since you have FI and you probably don't want to change the pump more than a couple of times a year unless you're upgrading it or something, don't let it get below ¼ tank sitting still or cruising steadily on a level surface.

 

lol... mine swings the full sweep of the gauge from empty to full on only 5 dollars of gas and continously varies as the car is driven. Ive taken on the averageing mehtod by eye as i drive to determine how much gas is left. Makes those long trips all the more suspensful. "Is it full? Empty!?!?!?!?" One of these days when the pump goes ill get a new in tank sender.

 

I think this is something GM didn't take into account when designing our cars. It's a normal thing with our cars mine does it too, and I know it gets on my nerves all the time. Every Balancing coil type guage like the ones in our cars work the same way but what some car manufactures started installing is an I.V.R. (instrument voltage regulator) which controls the voltage to the guages by oscillating the 5 volt signal. This keeps the guages from swinging back and forth. Our cars are not equiped with this which means the guages are always receiving a constant 5 volts.

 

It actually states in the owners manuel that the fuel gauge only reads correctly while "under load".