Improve mileage or horsepower on 2009 Toyota Yaris

[yarisito]

My car is stock. What upgrades can be done to improve either the power or the fuel economy?

[knobby bobby]

I removed the stock air filter and installed a K&N air filter and it improved gas mileage and performance. The yaris is meant to run with the stock muffler. A fart can will loose back pressure and power

[MadMax]

I removed the stock air filter and installed a K&N air filter and it improved gas mileage and performance. The yaris is meant to run with the stock muffler. A fart can will loose back pressure and power

That same "high performance" K&N is letting in a substantial more about of dirt and other particles into your engine. In the long run it's a bad idea.

As for performance out of a Yaris, it's an economy car. If you want performance, buy a sports car or just drive your Yaris as fast as it will go and enjoy the ride!

[myfirstyota]

Performance: 2zz swap
Mileage: slow down, drive less