Ford F150 - Trouble codes P0171, P0174 and P0401

I have a 1999 Ford F-150 V6 and recieving the following trouble codes P0171, P0174 and P0401. I have looked these codes up and cleaned the following items MAF sensor and the EGR valve. I have reset the computer after cleaning each of these parts only to have the check engine light to come back on. Does any one have any ideas?

Remove and clean the Throttle body. Where the EGR port goes through to the bottom of the Throttle body, it gets stopped up with carbon. At best, this will take care of it and at worst, it needs to be done from time to time anyway. I have been through the same thing with my truck and my Taurus, this cured both of them. Do that before you start buying parts.

It appears that the PCV valve has a plastic line to the bottom of the throtle body. There is a rubber elbow that connects the line to the throttle body. The rubber elbow had two splits,one in the elbow and one on the outside of the elbow. It appears this was caused by heat. There isn't much room but enough for small hands to remove it. This is a dealer item and cost $8.32 to replace. There is also another rubber elbow back by the PCV valve on the left side of the motor that connects to the back side of the intake and that one also had a split. I just used a plastic elbow from the parts store and added a small piece of tubing as a fix. I then disconnected the battery for ten minutes to allow the computer module to reset and this has fixed my problem for now. I will let everyone know if this fix last more that 30 days.

I also had a 0171-0174-p1506,and repaced o2,tbs,egr pos-sensor only to have it return time and again..I finally found the elbow on the back of the intake to be bad,,cant even see it had to feel for it!!! It was better but codes kept coming back and high idels also!! last alternative was the MAF..I cleaned it before but still probs. Put in new MAF and no luck..then after letting it run and warm upfor 5 mins. I heard a vac leak come on and back to the same ol crap!! The dirty culprit!!! was the elbow from the PVC tube under the intake in the front!!! Made a temp connector and great!! This never leaked till after it warmed up!!! What a pain in the XXX..Now running great....

HAD THE SAME IDLE PROBLEM AND THE SAME CODES AND FOUND A HOLE IN THE VACUME ELBOW UNDER THE INTAKE.

Hello, I have been looking through the forum and found this topic. My 98 has just started to do the same thing described by all, I check the codes and came up with the exact same ones P0171, P0174 and P1506. I am writing because I am trying to find out some more info on the location(s) of a cracked hose...ect, I do the most basic maintenance on my truck but I would like to start doing more, I just need someone with the time to explain and a little patience. I hope someone can help me, I have the repair manual and most all of the tools needed, I just need a little help with where to look and how to get there. LONG LIVE THE F-150

Hello, I found the elbow under the intake and of course it had a hole in it. I went to my local dealer and tried to order the part but they were not sure which one to get, they showed me a layout of parts on the net but even that was hard to find the right one, the service guy finaly said I think that this is the one.(but I would rather not spend $15 unless I am 100%) Can someone let me know what the part number is for the elbow that is needed, I would really appreciate it. LONG LIVE THE 1-150

I'd take the hose off the truck, that way the parts guy would be able to match it up to the right one.
Also to find a vacuum leak, use a section of vacuum hose(I'd use a new one so as not to have the black on the inside of the ear) put it to your ear and then move it around under the hood.

I am surprised your parts guy could not identify the correct hose by using your VIN number.

The part number from the dealer is F65Z-6762-CA
The cost was $14.44, thats with tax and everything.
It fixed my 171 & 174 codes.

Thanks Fordtruckin I really appreciate it, I am sure now that I will get the right one. The price he quoted me was around the same amount, so he probably had the right part but I just did not want to spend the money unless I was sure. Thanks again for everyone's help.