Q: car hesitates when starting, sluggish when driving and put 15 gallons of gas in gauge still says low fuel

It sounds like you may have a couple of different issues going on. There are a number of things that may cause the car to hesitate when accelerating such as low fuel pressure, a dirty or faulty mass air flow sensor, clogged or dirty fuel injectors, a faulty throttle position sensor or potentially a bad fuel pump. Other things like a vacuum leak or faulty ignition components such as bad spark plugs or spark plug wires may also cause this kind of hesitation when accelerating.

The fuel gauge fluctuation is a problem likely related to your fuel tank sending unit. The fuel gauge sending unit is a small float type component (or sensor) inside your fuel tank that measures the level of the fuel inside the tank. As the fuel level drops, this change is detected and relayed in the form of a signal to the car’s computer which then displays the reading on the fuel gauge in your dash. I would recommend having an expert from YourMechanic come to your location to diagnose and repair your vehicle.