2008 Accord Engine Malfunction Light- Poor gas mileage

My 2008 Honda Accord 's dashboard Engine Malfunction Light got lit. I have driven a further 4 kilometers and stopped at a lube station and found that oil level is a little low.

Did an engine flush and refilled with synthetic oil. The MFL light is gone after a minute of starting and it stayed out.

Now the problem that I am facing is poor gas mileage. I can literally see the fuel guage going down while driving . A full tank now gets me around 200 KM rather than 550-600 which I usually get.

Google search suggested an ECU reset. Is this safe ? or should the car need to go to the service station?

Thanks for the help.

An ECU reset is not the answer and odds are the service station (which I assume to mean a gasoline selling facility) may not be the answer either.

What needs to be done (assuming the engine appears to run fine) is have the car scanned for codes. Many chain type auto parts stores will do this for you free. Knowing any codes will provide a starting point for diagnosis.

If the fuel mileage has really gotten that bad I see no way the engine cannot be running like garbage, idling rough, belching black smoke, showing a flashing CEL, and so on.
If it is doing the above then I might suspect the fuel pressure regulator has completely failed.