Terios MAF sensor


Hi all I’m new on here so I hope I’m not bringing up stuff already covered. I did look to see if any discussions would answer my question but couldn’t see anything.
So I have a 2006 Terios DOHC 1.5 2wd.
Been having issues with the EML coming on codes say P0135 P0130 which I know relates to the Oxygen sensors.
Both post and pre Cat have been replaced but to no avail the light keeps returning. I might add the engine is running well, there is some whiff of petrol fumes occasionally though.
There doesn’t appear to be any vacuum or exhaust leaks. So I’m at a loss on that one any help or advice if similar problem experienced would be grateful.
In the course of trying to find any related potential causes I have been trying to locate the Mass Air Flow sensor! But I cannot, it’s not between the air intake and filter.
Can anyone advise please?
Many thanks.