Need help/advice. I had trouble codes indicating than my MAF was dirty. I cleaned it per the instructions given by Oil Dan in the how to section. Now I am getting bad gas mileage. Trouble codes are cleared without the CEL. My truck is a 2002 F-150 Harley Davidson w/supercharged 5.4 v-8. Need Help!!! original trouble codes:P0171 P0174 lean codes Auto Zone.

 

replace the PCV valve on the passenger side valve cover

 

Thanks Faster150, will try PCV fix, will post results. Thanks

 

the PCV valves will stick open and throw a lean code.