While driving, no matter how slow or fast, if I hit any bumps or brake/accelerate the fuel gauge is all over the place. Not the normal GM float, I'm talking erratic movement. While cruising on a smooth road it the needle will move just a little at random. Once I stop for a minute and sit still it will settle down and read correctly.

I have a new sending unit in the car and it does the same thing as it did with the old one. Any ideas?

 

mine does the same thing it moves all around from 1/2 tank to full!
please help

AK

 

hey, at least you have a fuel gauge.

 

dude, my gauge is dumb. I can get over 100 miles after filling it up and it will still read full. then when i get to a quarter tank it will only take about twenty miles before its glued to the 'e' mark. heres another one, how about when you go home for the night and your car is sitting at a quarter tank, then the next morning you go to start it and its at a quarter tank, then you drive somewhere and stop, then it glues to 'e' and it suddenly becomes a rush to the nearest gas station. im sure i cant be the only one with that one. theres gotta be a fix for this....

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1987 LG4 Camaro z28
Modifications- Flowmaster 80 series, KN airfilter, high flow cat, 180* stat, edelbrock performer intake manifold, msd blaster coil, ascd big block hood, panasonic cd player, rockford everything else.

 

Your post was hilarious. I can tottaly relate to that. I have a 92 z28. I just took out the fuel tank last night to see if i can find the problem. Ill keep you posted

 

i did find this on the net. Hope this helps. I wish i would have saw this before i took out the tank but o well


I own a shop, and what I would do is this; Find the wires that go to the tank as close to the tank as you can. Use a multi-meter, and with it set to DC volts find the power wire to the gauge in the dash. Make sure it has voltage to it. Second; remove the battery (+) cable, set your meter to ohms X-1 scale, and probe the wires to find the ground wire at the tank. You should get a reading that will peg the meter, if not find out why the wire doesn't have a good ground. It may be corroded where it attaches to the body, and/or the ground from the battery is not attached or making a good ground to the body/frame. This is 90% of the time the problem. Remove the gauge from the dash, and probe it for power, and the other wire will be the ground. Make a seprate ground wire, and touch it to this terminal with the switch in the on position. The gauge should move up right away if you have power and ground to it. If it doesn't, the gauge is bad. The register inside the tank works by giving the gauge more or less ground by moving up an down controling the resistance (ground) to the gauge in the dash. You may even have a broke wire that comes from the tank to the gauge, so by making your own ground you test the gauge. Many times in a vehicle that old, the wires going to the tank will be cut or broken. If you trouble shoot the system as I have suggested, and you still have no gauge working, the wires are good, and the gauge is good, then the only thing left is a faulty register inside the tank.
Glad to help out, Good Luck!!!

 

You might want to clean and tighten the ground under the driver's side rear seat cushion. That's what it was on my '87 IROC.