For some days now my car (98 STI) has an increased fuel consumption, i just chance the plugs and a the water temp sensor believing that was the problem but i dont see any difference. I check the sensors in the Power FC menu and i have seen that the PGS is flashing.
What is the PGS?

 

Purge solenoid.. normal for it to flash.

The most likely culprit is the lambda sensor..

go to ETC ==> Function Select and scroll to the bottom most option and scroll right.. 02 Feedback press down arrow to turn the lambda sensor off and up arrow to turn it back on.. unfortunatly it ia japanese symbol so not obvious off and on.

Try it off for a tank
Simon

 

Thanks Simon, i will try it with O2 feddback off.

 

another thing would be accidentally altering the MAF setting on the Setting ==> Airflow for example..

Simon

 

I haven't chance the maf's settings at all,
it seems that the problem is with my O2 sensor, today at the daily route to work, with the O2 feedback off the consumption decreased significantly.

 

nice one