WE've cussed and discussed MPG on the SX4, over and over and over again, for at least the last three years, that I've been on this forum.
The answer remains exactly the same.
Why not go back and read some of those very good threads?
Stop driving it like you stole it! That's #1.
Don't run around with your tires all soft and squishy. 33psi in SX4 tires is a crime and a shame. Jack those tires up to about 38 to 42 psi if you want better performance and better MPG's.
Then stomp the GO pedal like you were walking on eggs. Easy does it!
A K&N Air Cleaner will help, and so will using a Anti-Friction additive like "Prolong". I've done all of the above with my own 2009 SX4 iAWD and I actually did get pretty good mileage. The FWD cars will always get better MPG than the AWD's. That's just simple mechanics.
With all the Suzuki dealers in my area CLOSED, I jumped ship, so to speak and traded my SX4 off for a Kia Soul. I've used all the above tips on my new Soul and I'm getting mileage like this: (as seen on my Scan Gauge II )
The SX4 is capable of decent MPG, but not unless you're willing to work at it.