2009 Buick LaCrosse - Fuel Level started reading funny. Any ideas?

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Aug 2, 2014
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It may well be from sitting so long, this issue was also very common with GM Saab cars. Saab had a TSB that said to first try 20oz of Techron in an low tank then fill it before going into any actual repairs.
I have seen this work well on other vehicles like Chevy Venture, Grand Prix, Buicks, a VW Golf and a few others, some it doesnt help at all. Definitely worth trying before getting any deeper into it.
Agreed, very common for these vehicles and fuel system cleaners have always been my recommendation for it. Not a guaranteed fix but more often than not it does help. I've always recommended half a can of Berryman B-12 on a near empty tank, drive it down the highway until the gas light comes on. Put the other half can in, fill it up and on the next tank Gumout with PEA/Techron.

At the very least if it should make a noticeable difference.
 

3800Fan

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Jan 14, 2017
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Agreed, very common for these vehicles and fuel system cleaners have always been my recommendation for it. Not a guaranteed fix but more often than not it does help. I've always recommended half a can of Berryman B-12 on a near empty tank, drive it down the highway until the gas light comes on. Put the other half can in, fill it up and on the next tank Gumout with PEA/Techron.

At the very least if it should make a noticeable difference.
I almost went the berryman route but I read some things about people ending up with engine troubles after using it so I decided on Chevron Techron. Two treatments is the same price as redline fuel system treatment.
 
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Jul 18, 2010
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Colorado
I was recently given a 2002 Blazer and was warned to fill it when the needle shows a 1/2 tank because past that the needle will bounce up and down.
I put a bottle of Techron in then followed with a bottle of MMO.
Now it does not fluctuate.
So not trusting it I fill it when it hits 1/2 and it takes 9 or so gallons for an 18 gallon tank, pretty accurate.
The last fill up I let it go almost to 1/4 to see and it again took 9 gallons.
Not going to trust it.
I now reset the trip odometer and when it shows 140 miles I fill it.
The blazer gets 14 MPG so 140 miles takes 10 or so gallons.
 
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Nov 22, 2004
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Texas
Run a double dose of TECHRON. GM TSB's actually instructs you to do this as a 1st step. The contacts on the sender unit gets sulpher build up from low tier gas. Only Techron has proven to be able to fix this issue. If it doesn't then there is a problem with the unit and you have to replace it. I know FCA had issues with RAM fuel pumps and they had to be replaced because the contacts were cheaply made and wore off early....I had to replace the fuel pump in my RAM for this issue.

Try Techron 1st...
 
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