I haven't been here for awhile but something happened that I felt I must share with you..
I have a 2015 EX that now has 40,000 miles and for the last year I noticed my mileage was not as much as when new. I ordered a cabin filter and decided to get a factory engine air filter as well.
On the first drive after my son installed it I glanced down and it was reading 47 MPG ! I just couldn't believe how much my MPG had increased and it even felt more responsive ..like I was driving in Sport mode. The old filter was not nasty looking but looked grey but the increase in mileage and and response was dramatic! I've had many cars in over 40 years of driving, fast slow new and old , but have never had such a improvement from such a simple, low cost part as putting in the Honda factory filter..Even now 2 months later I'm still having trouble believing how much my MPG has increased ..

 

Are you sure it wasn't a tail wind ;-)

 

maybe it's summer blend gas? not sure if they do that where you live but up in chicagoland they switch over about now and the MPG difference is noticeable.

 

Bossharp - I notice you are in Ocala, Florida, and I bet that has a lot to do with the gray or blackish filter you took out. Florida has that dirt dust that lands on EVERYTHING. It's also super fine and even tacky enough to grab onto more crap. The stuff is relentless to say the least. I buy my NAPA filters during March each year because they offer a farm and fleet special sale price to the public as long as we buy more than three filters. Midwest farm fields and bugs have me changing my engine filter twice a year and my cabin filter 2-3 time each year. The frequent cabin filters can also be blamed on a neighbors tree.

Congrats on the improvement!

 

I recently had the B-1 maintenance minder service.
Also had the Cabin Filter and Engine Filter replaced. As well as an Oil and Filter change.

I had some "trouble" with the dealership overfilling the Oil Change. I had to have them drain some oil to get it below the overfill range.

I've noticed an improvement in MPG, but there are too many factors for me to really tell.
I doubt it could have anything to do with the Cabin Filter.
The biggest jump I noticed, and it may be coincidence or fully imagined, seemed to coincide with them draining the overfill of the oil.

But between Cabin Filter change, Engine Filter Change, and Oil and Filter change, as well as before mentioned possible Winter to Summer Fuel Blend changes, as well as outside temperatures simply becoming warmer, I can't narrow it down to anything singular.
In fact, it's probably a combination of everything. With warmer temperatures, I think maybe being the biggest factor.