Q: Doing less MPG than before and I sometime feel heavy slow during driving

This may be related to what is called a mass air flow sensor. This is a unit that monitors the air intake as it is mixed with fuel prior to being injected into the motor. This unit sends a signal to the computer which then directs the fuel injection to add more or less fuel to make the correct air/fuel ratio. When this is not working correctly, you will notice a decrease in fuel mileage as well as a sluggish feeling when driving. The car may struggle to accelerate and will usually emit a smell of fuel. I would recommend having an expert from YourMechanic come to your location to take a look at the car to properly diagnose your vehicle’s odor and mileage issues.