2012 Buick Enclave Fuel Gauge fluctuate

I have a 2012 Buick Enclave that the fuel gauge fluctuate. It is not in sync with digital readings. When parking down hill the gauge goes to full. After driving a while the needle will move up a little. Even when on level ground it will fluctuate.

How Many Miles On The Vehicle ?
You Are Out Of The Factory Warranty Coverage ?


Some fluctuation is normal. And it is normal for the guage to move up after driving a little. This happens on my Corolla also. Why? I don’t know. But it does. Also, the guage will go up or down a little depending on whether you are going uphill or downhill. That’s normal, caused by the top of the fuel surface shifting in the tank. Whether it goes up or down depends on where the fuel float of the sender is located.

I’m not sure what you mean by digital readings. But if this is something that is more noticeable than before, and just recently started to happen, the two main suspects would be the in-tank sender unit that is sticking, the sender’s resistor contacts that have become corroded, or the guage or associated guage voltage regulator that is on the fritz. Any good Buick mechanic could narrow it down with some simple testing. Most often this problem is caused by a faulty sender unit.

Every car I’ve ever owned has done this to some extent: The gauge reads a little lower when the car is started after sitting overnight. After a little driving, the gauge reads a little higher. This is really only noticeable at levels lower than ½ tank. Since the gas in the tank doesn’t heat up appreciably as you drive, and the gauge is driven by a voltage regulator and temperature-compensated, I’ve never understood this either. But still every car I’ve owned from a 1970 to my current 2006 still does it somewhat.

George has offered some good ideas. However, it just might be normal. The last portion of the travel in gas gages systems is “damped” to prevent the needle from fluctuating excessively due to the sloshing aound of the gas in the tank. That manifests itself as the needle coming rapidly to alomost it’s actual reading and then slowly moving through that last 1/4 tank (or whatever the system is designed to “damp” at).

The gage goes to FULL when parking headed down a hill because the sensor is apparently located toward the from of the tank…and that’s where all the gas runs to. That being true, the gage would fluctuate more during normal driving than gages whose senders were more in the middle off the tank, just because of the gas moving around.

this sounds to me to be just sloppy design on Buick’s part.