My 1.3 city 2012 manual has 63K on the oddo and I am experiencing a similar dip in KMPL aswell. It used to do 16 to 17KMPL in my daily run from Thokar to DHA in Lahore but nowadays it has dropped to between 11 to 13 KMPL.
What i am sure about is my driving style which has not changed at all. One factor which I think acting here is high environmental temperature?? I am not sure. I don't think it was doing a mileage this bad during last summers..
Apart from the mileage, let me share one more experience which I am quite sure several others would second. My car doesn't have a smooth pick when in low gears with RPM between 1000 & 2500..it kind of gives a lagging feel when kicked to speed up in a higher gear e.g. while throttling from a speed of 30/40KMPH in the 3rd gear after decelerating from suppose 50/60 KMPH. By the way it gives a good pick in higher revs i.e. above 2600.
Just to share the history, up to 40K KMs on the oddo, i always enjoyed the smoothness and quick pick in low speeds and gears...after the 40K KMs check up where they did the tappet adjustment as a part of the tuning, as well as serviced the Throttle body (For the first time), there on the silky feel i though was lost and never returned.
And yes, the Fuel Filter was replaced at the 40K KMS service as per the manual. Just to share that the fuel filter which was removed was fairly good to go for another 20K KMS atleast.
Upon consulting Honda Gateway experts on a test drive, they drove with a slightly heavy foot and the feel was not there. While i drove and asked them to experience the lag, the weirdest comment which i was expecting was passed on by that fairly decent guy: "Sir g thori jinni race dain, phir dekhain kaisay dorti hai" :s
Anyways, got the tuning done at 45K KM oil change and the mechanic from Gateway who was doing it this time, started showing me: "dekho sir g, tappet kinnay tight keetay hoay see!!"
I got the plugs changed also - costing around 10K! and I always change the air-filter after 5000Kms although they can go up to 10,000Kms.
Nothing helped. Still the response did not improve. On top of that, i feel that my car is not giving me any good mileage in terms of KMPL!!
Anyone with similar observation and advisable solutions?