Honda City 2003 Fuel Average Problem

[pwuser169139276991]

Hello Everyone,
Need your help urgently.

I have honda city 2004 manual model with original engine. The car was perfectly fine but from last month giving worst fuel average of 7KM per liter.
-Recently Oil Changed 10-40
-Cleaning and tuning done.
-Installed new plugs.

But nothing worked. Need your suggestions what can be the possible cause of this worst fuel average.

[msabbasi]

Did the fuel average become bad after the "cleaning and tuning"? Or was the cleaning and tuning done to fix the fuel average problem. By the way does your car also have poor acceleration along with bad fuel economy?

You did not mention the type of City. I think 2003 was the crossover year from 3rd gen (EXI) to 4th gen (i-DSI).

[sindhpolice114]

maybe you should try using a thinner oil like 5W-30 or 10W-30 if it does not cause oil burning.

Maybe your fuel injectors are dirty, or check your Air filter as well, it could also be that your fuel filter is choked.

[pwuser169139276991]

Cleaning and tuning done to fix the problem of fuel avg. I'm noticing it goes bad after oil change. Before I was using 20/50 but this time I shifted to 10/40, after oil change the fuel avg is dropped. And it's the IDSI city. End of 2003

[msabbasi]

Oil grade change should not have a huge impact on fuel economy. I am leaning towards a blocked catalytic converter Symptoms of a blocked cat con are poor fuel economy, poor acceleration and inability to reach top speed on the motorway. In Pakistan the mechanics remove the O2 sensor upstream of the cat and insert a mini camera to have a look at the honeycomb. In other countries air pressure is applied at the same O2 sensor and pressure drop is measured across the cat. A good cat will have almost no pressure drop.

[pwuser170619393089]

Honda city2003 no cat in this model