p171,p174 codes on 2004 Ford F-150 Heritage

got truck checked out,replaced pcv hose passenger side, 3 weeks later throws codes again,any suggestions?

by in Kansas City, KS on February 11, 2011
3 answers
ANSWER by on February 11, 2011
You have a vac leak. You have either missed other vac hose/connections or you have a intake manifold leak. If you would provide more info on your truck I believe there might be a TSB on that truck. Contact me at autoknowhow@gmail.com.
ANSWER by on February 12, 2011
Vacuum leak or a failed MAF sensor. Zee
ANSWER by on February 12, 2011
If it is a 4.2 liter engine you will have to replace the intake spacer.VERY COMMON problem.
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