Hey guy new to the site here and just recently hit a problem. Ive got a 2000 f150 with a 5.4 and 135,000 miles. The other day it was driving fine then i stopped and got gas and after that it was boggy and running rough so i thought bad gas but i ran through that gas and got more at a different store. The cel came on i got it checked it was misfire cylinder 1 so i put new cop, spark plug, and injector. Unhooked the battery and then the light came back on so i ran the code and now im getting a p0171. I checked the pcv and sprayed around the intake and vaccum lines. I also checked the pcv hose and elbow in the back and i found nothing its a fairly new hose. So any ideas would be great and it does run rough it shutters alot. Thanks!

 

mine was burnt / hard 1/4 inch vacuum lines above the drivers valve cover that run the EGR system. Two small hoses about 8 inches long.

 

I checked em out today and didn't see any issues but ill give em a once over again tomorrow and see what i come up with.