I fairly recently purchased a 2008 Jeep Patriot Limited. It has the 2.4 and a 5-speed manual. I've owned it for over a month now and for the most part I have been happy with it. I fill up every time I get gas and reset the trip odometer so I can check my mileage. Up until today I have been getting right around 20 MPG and this has been a disappointment. I have been towing with it quite a bit but I just have a 5x8 trailer and I stay off the highway when I'm using it.
After reading what this forum says they get with their Patriots I decided to change the plugs, air filter, and put a can of fuel system cleaner in the tank. The filter was practically black it was so dirty and the gap on the plugs was about twice what it should be (although I was happy to see they were very clean). I'm hoping this will bring my mileage up to where you guys are.
Side note: I bought a cabin filter while I was getting everything else and when I went to swap them out there was no existing cabin filter there. I put the new one in and went on my way but can any damage come from not having one? I have no idea how long the vehicle was without one.