I just noticed a very large difference in instantaneous and average MPG when replacing my engine air filter (EAF) last week. The instantaneous MPG went up about 2-5 MPG but the average went up about 1.9 mpg over the first tank for the same commute (drive) and same weather (it was obvious on the first OW commute that something drastic changed to MPG). Has anyone else noticed this?

Details:
- Engine air filter typically replaced once/year in April
* last change 14-Apr-22 at 42057 miles
- PoAuto (Amazon) replacement like-for-like (I bought several in advance)
- EAF replaced at 51736 last week

 

Yes keeping up on maintenance will get your lost HP back. I would use a Honda brand air filter for even better results.

 

Did you notice MPG improvements (you mentioned hp)?

 

Get yourself a K&N filter and then tell us about your mileage increase. I can, with the a clean K&N, get 40mpg. I have a 2018 EX-L.