2012 JKU out of fuel at 1/4 on Gauge

Seafoam won’t hurt anything, but it will not cure a bad fuel level sender. Tank needs to come out and fuel level sender replaced. And used vehicles have no mandated warranty.

The Jerry can and run it till it's empty and fill it up with 5 gallons is a smart idea. At least it will tell you how many miles you can go on a full tank. If it's your daily driver style driving then it's not a big priority. Once you get within 100 miles of that empty refill it. It's not a solution, but it's a good practice until you get it repaired. I bet if you look at YouTube you will find some easy drop down tank procedures and my suggestion would be to drain the tank as far as it can go. I think it's a job. You can do it yourself. I don't think Jeep has a setup where you can access the top of the gas tank from inside. I know Volkswagen Jetta you could take the back seat out bench and you could have access right there to the top of the can gas can to replace any sending units or such.