Good mechanic to fix Honda City 2018 average issue

[rizvi98ahmad]

I have a Honda City 1.3 Prismatic 2018.
In the beginning the car gave good average 11 to 13 in city and 15 to 18 on highway depending on A.C usage.

The issue I can't seem to diagnose. If it's air flow sensors issue, fuel pump issue, injectors issue, oxygen sensor issue or catalytic converter cleaning issue.
Have already changed the spark plugs at 95000 and it had no effect, the car goes through oil change and tuning at fixed times all is documented. But this low fuel average issue can't be fixed.

I want someone to recommend me a good mechanic/ workshop where this issue can be properly identified and properly professionally fixed. Please guys help 🥺. 🏼

[syednayl]

What is the current average right now, have you had your catalytic convertor checked to see if there is a blockage there?

Any other abnormality you have noticed in your driving?

[rizvi98ahmad]

So no I have not had it got checked yet. But another abnormality would be a little bit lag in the acceleration and also the fuel gauge is not proper, never shows the correct amount of fuel.

[Parker1]

Hi,

Can you advise what is the total mileage right now?
What mechanical parts have been changed so far?
What is the current mileage of car?
Which Oil grade are you using?