When I removed the air filter housing I noticed that there is an upper filter of some sort in the lid, what is that all about and does it need replacing when the other filter is replaced? Is it even serviceable?

 

What car? What engine? Photo?

 

2009 RX350. Sorry I didn't take a picture of it but it is a mesh looking filter looking thing in the lid of the air filter housing.

 

There is only one air filter element.

 

That's the charcoal filter to meet California's strict emissions regulations. You don't need to change it / service it but I just rip it out of all of my cars.

 

Okay, so removing it won't throw a code or anything?

 

Nope. I have had it out of my Highlander for 10+ years and my RX for 1+ year. If anything, there is slightly less restriction with it out of place. Makes holding the air box by hand easier too.

 

Add a K&N drop in filter & be done.....