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Crazy Fuel Gauge


New Member
Feb 6, 2018
Heber Springs, AR, USA
At every fill up, the fuel gauge goes crazy for a while. Up and down, then at half full, then settles at full. The needle stays at full till almost empty, then moves to just short of full. Thanks!!!
1997 wrangler, 4 cyl.


Staff Member
Sep 28, 2015
Salem, Oregon
Sounds like your float sensor inside the tank is going bad. If this is the case, you need a whole new fuel pump assembly, as I don't believe they sell the sensor by itself.
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TJ Enthusiast
Supporting Member
Nov 21, 2018
San Antonio, TX
I'd guess either bad gauge or bad float. I know the YJs were notorious for busted gauges, mine had the same issue where it was either always full or random but never reliable. Given that it's a '97 I wouldn't be surprised if it was still using the bad gauge the YJ used.

If it's a bad float then you have to... what @Chris just posted.

If you don't know the float is literally a floating, buoyant doohickey on an arm that pivots about the fuel pump assembly in the gas tank. Based on where the arm has rotated a sensor will read it and tell the gauge what level the tank is at. I have seen one of those arms stick before but that was on a Chevy, no idea what the one in a '97 TJ looks like. Depending on how much work you want to go through you could buy a new one, take the old one out and give it a look over to see if it seems anything purely mechanical you could fix and give it a shot... or just replace it and be done with it (that's what I'd do honestly).
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Supporting Member
Jan 12, 2019
Vegas Baby
I have a fuel sending unit issue too. I have an Check Engine light and the code said that the sending unit voltage was low. I swapped the sending unit and it didn't solve the issue. The gas gauge comes and goes while I'm driving- it seems to be a short or a connection somewhere that is making and losing contact as it hits bumps. Looking for guidance if there are any "known issues" with connections.