2012 Sonata 2.0T . When I turn my car on it seems like my miles till empty reading on my dash is going up and down 1 digit at a time till it registers. But it’s always different every time I turn car on. I’ll turn on it will say 54 miles till empty. I’ll turn off and on again then it will say 128 miles till empty. It just started doing this. Any suggestions on what the problem could be?