Q: Engine lost power and now won't start.

Hi there. This can be caused by any number of different problems. Most of the time if the vehicle starts to gradually lose power and then it turns off it is caused by a failing fuel pump. It can be a sensor or other electrical issue, but the fuel system is the most common. You can do a preliminary check by tuning the key on and listening for a buzzing from the fuel tank indicating that the fuel pump is turning on. If you do not hear anything then the pump has likely failed. If it comes on then a fuel pressure test with a pressure gauge needs to be performed. For a test like this and a pending fuel pump replacement you should enlist the assistance of a certified mechanic, like one from YourMechanic, to get your car started again.