Ive been having a bit of a hassle with the infamous P0174/P0171 codes which started last week on my 02' 4.6L F150 which also accompanied rough idling and stalls at stoplights. Running down the road seemed fine though. I took my code readers suggestion first which was to check the oil dipstick and see if it had popped out- it wasnt, the tube was broken in half, which led to some fun removing and replacing that. Once I got done with that chore, I went to the next suggestion and cleaned the MAF sensor, changed the fuel filter and same story. I popped the hood and heard loud hissing coming from behind the intake right where the PCV connects to the intake. My question is since my 4.6L seems to be a bit of a bastard child and nothing matches the auto parts place, what fitting goes back there into the intake on a Windsor 4.6L? I picked up a PCV valve but the only one they said would fit an F150 4.6L from 1997-2006 doesnt fit and I ended up mixing and matching mine (a larger grey plastic PCV which screws into the valve cover on the passenger side) and everything I see online is a 3/8" hose elbow which mine definitely is not, it looks more like a "T" from the best I can tell and much larger diameter hose. Any help you folks can offer would be great

 

Hey, I am currently having the exact same codes and symptoms on my 1997 5.4l F150. The two codes (P0171 & P0174) went on last week, so the first thing that I had checked was the vacuum hoses and sure enough, there is quite a large hole in the hose that connects the PCV valve to the back of my intake manifold. I plan to get a new hose from the dealer today and try to change it out soon. It seems odd to me that you are having such a hard time finding parts that fit your particular truck, as far as i know this is a pretty common problem with both our trucks. Hopefully you find the right parts with out too much trouble!