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Discussion Starter #1
I get in the car this morning, tank at 3/4. Drive about 45 minutes, nothing too aggressive (no more than usual). Pull up to a stop light to wait, and just happen to look at the gas gauge - which now reads under 1/4! What the ----? Do I have a leak, hit the line, this just can't be right? Light turns green, go half a mile, and the gauge slowly climbs back up to 5/8 or so - where I would expect it to be. Wasn't on a hill (up or down), didn't pound the pedal (today), nothing unusual that I know of - except the mysterious loss and equally mysterious reappearance of gas in my tank. Anyone else had this phantom? :confused:

Bob
 

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Formerly 06 STS-V, now 13 XTS
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I get in the car this morning, tank at 3/4. Drive about 45 minutes, nothing too aggressive (no more than usual). Pull up to a stop light to wait, and just happen to look at the gas gauge - which now reads under 1/4! What the ----? Do I have a leak, hit the line, this just can't be right? Light turns green, go half a mile, and the gauge slowly climbs back up to 5/8 or so - where I would expect it to be. Wasn't on a hill (up or down), didn't pound the pedal (today), nothing unusual that I know of - except the mysterious loss and equally mysterious reappearance of gas in my tank. Anyone else had this phantom? :confused:

Bob
I have not experienced this in my STS-V, but my old 99 STS, my 02 Eldorado and my 01 Chevy Silverado all experienced the same thing. It began like that and then eventually started reporting completely empty or completely full all of the time (even jumping back and forth occasionally).

The issue in each case was a bad sending unit on the fuel pump. All were replaced under warranty and have been fine since. GM is famous for this problem, but I would have thought that they would have a better design by now with these newer cars.

Just keep an eye on the gauge and if it starts getting worse, take it into the dealer and get them to check the sending unit.
 

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Discussion Starter #3
Thanks. I will stop by Monday and let them look at it with that in mind. I recall a similar thing in my sisters Denali as well. I reset the A mileage every time I fill up, so I know how much I have in the tank, but it is annoying / bordering on panic when you casually look over and see it down near "E".

Bob
 

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I have seen the guage change depending on what grade you are on, sometimes by 1/4 tank, but not to the extent you seem to be experiencing.
 

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Discussion Starter #6
No, this happens randomly when the car is perfectly level, driving or stopped. Just has a mind of its own. As soon as I run the tank down to about 1/2 again, I will stop by the dealer and have them take a look. I had to fill up over the weekend (how would he know?) and it isn't doing it with a full tank.

bob
 

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Formerly 06 STS-V, now 13 XTS
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No, this happens randomly when the car is perfectly level, driving or stopped. Just has a mind of its own. As soon as I run the tank down to about 1/2 again, I will stop by the dealer and have them take a look. I had to fill up over the weekend (how would he know?) and it isn't doing it with a full tank.

bob
Oh yeah... that is almost definitely the sending unit based on my past experiences. It never did it on any of my cars until I got to around 1/2 tank or so. The lower it got, the worse it got.
 

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My car does the same thing. Does your mileage jump as well on your DIC? one minute ill be in the car and it will say 100 miles to empty, ill shut off the car, get out and then start it again and ill be at like 69 miles to empty
 
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