I have a 2011 lexus ct200h and my car is making noise coming from underneath the car. Its like a rattling metal and it goes away every time I stepped on the gas pedal. Does anyone know what is going on with my car?

 

Chances are your heat shield got loose and is causing the rattling. You can visit local muffler shop and have them fasten it back on or remove it completely, it's pretty common thing in cars.