My friend's 2003 expedition read these codes the other day, PO171 and PO174. If that means its running lean how do I fix it? Have any of yall had this same problem?

Thanks for the help

 

My 2003 Expedition 5.4 had the Check Engine Light come on, had the 0174 lean code read, and it was my vacum lines - apparenlty its really common for the rubber elbow on the PCV valve to split (near passenger side) mine hadn't split, but was perished - I didn't have the elbow to replace it, so I just used high temp water hose and a 90 degrees joiner - worked well and after my battery was diconnected I haven't had any more light or codes

Google Expedition PCV elbow, and there will be pictures of the location and part numbers etc..

 

yep had some problem @ 130k miles, same error codes and same solution: replace that elbow piece. About 10k miles later though a coil failed and then replaced all 8 coils and plugs. Running well now!

 

Mine was the elbow on the very back of the upper intake underneath it a little..pita to get to...bought the whole assy from back of intake to Pcv and to front of intake for 40 bucks from Planet Ford...huge spyder assy allmost every vac line on passenger side. 5.4L btw if there is any difference.

 

Could be a bunch of things. It is more than likely an air leak. I was getting same codes. Replace egr, pcv, iac,and all associated plumbing. Ended up being a cracked intake

 

Could be a bunch of things. It is more than likely an air leak. I was getting same codes. Replace egr, pcv, iac,and all associated plumbing. Ended up being a cracked intake manifold. Where it was cracked we couldn't get starting fluid or smoke. Tester into that area.