I need some help. The checklight came on in my 2001 sports trac a few weeks ago. I replaced the EGR valve and cleaned theout with carb cleaner. Once again the check engine light came. I took it to Auto Zone and had it checked the only code on it was 0409. The guy working there said it ment Flow Insuficent and it could be the egr cylinode. Does anybody have any clues on what I should replace first.