My wife's 2014 Santa Fe (3rd row seating with V6) starting having a problem on the last 4 or 5 fuel fill ups. When the fuel level gets to about a 1/4 tank, the engine rpm will drop some and act like it's going to die when coming to a stop at a red light or stop sign. Doesn't do it often, but that's when she notices it doing it. I was actually in the car when it did it once. No check engine light will come on when this happens, so the dealership said it will be hard to diagnose unless it does it when they test drive it. It happened again today, but the tank is at 3/4. She has an appointment for this Friday. We're hoping they find the problem. We tried switching brands of gas and it went through an entire tank without doing it, so she went back the normal gas station and it went through that tank ok too. She filled up again at a different gas station that doesn't have ethanol and that's when it did it today at 3/4 tank. Anyone else experienced this problem or know what it might be? Starting to think it's maybe not the gas and maybe the fuel pump? Any thoughts are appreciated.