Hi Scotty,
I have an automatic 07 matrix, 330km, never had problems, no major accidents. Fuel economy is dropping used to get 28 mpg now getting 23-24 mpg. Regular maintenance, oil changes, air filter, mass flow cleaned, throttle body, new spark plugs. P0420 code comes up with nothing else I would clear it and won’t see for a year, right around when the weather starts to get cold here in Canada. Im thinking of cleaning my fuel injectors, then fuel filter, and changing the catalytic converter. Original fuel filters and fuel pump.
Could you let me know what you would do?
Thanks Tman
It's likely just the result of wear and tear. Regardless of how well a vehicle is maintained, MPG goes down with age as different parts become less efficient from wear.
Jack it up see if any brakes are dragging, check cc joints. Check air in tires, I usually go up 5 lbs in all over recommended with good tires. Correct previous answer ( tired motor) may be main reason.
