This from another Lexus forum on the Lexus Nav system
"yep the NAV looks nice and all but is very disappointing in its
functionality. Maps are freakin old and the user interface is crap. For
$2000+ extra I would think it would work as good as a garmin or similar
unit."
The manual has step by step instructions on cabin filter change.The cabin filter access is in the back of the glove compartment.
The air filter is in a box toward the front on the passenger side of vehicle under the cover.
Take the air and cabin filter out and look at them.If very dirty chage them or just do a change to give you peace of mind.Both filters are very easy to change and not very expensive.