Hey all.

I've been getting a bit light-headed and slight headaches in my 2003 Corolla S I just bought.
I just changed out the air filter and cabin filter, hoping that will help.

We had it inspected before purchasing and the mechanic said nothing was wrong.
I am thinking about taking it a dealer to do diagnostics on it.

Anyone had this problem? What could it be?
Would an emissions problem do this?

Any help would be greatly appreciated since I spend about 2 hours a day driving in it.
Thanks.
kt