My 2004 5.4 3v also was stalling at idle, had a check engine light and codes P0171 & P 0174, lean in both banks. I replaced the MAF and the vapor management valve mentioned earlier on this post but neither of these solved the problem. It turned out to be the vacuum line from the back side of the intake manifold had come loose. I could see it with a mirror and flashlight but could not get my hand on it. It was just out of reach. However, after removing the fuel rail there was enough room to get a hand in there to fix it. The truck is running like new again. Hope this helps anyone with the same problem.

 

One more thing, the vacuum line I mentioned in the previous note is the one going to the fuel rail transducer on the driver's side of the engine. It is an orange line in a convoluted or serrated tubing and not easily recognizable as a vacuum line. A friend who is a Ford service engineer was also puzzled by this problem at the onset but he is the one who eventually found the vacuum line minus any vacuum. Also, on the last diagnostic test before getting it fixed, I too had the P2195 code for the O2 sensor malfunctioning.

 

Thats nice!
Any idea on how they found out, or fixed it?

 

Thanks mate!!
Will check this out in the weekend!!

 

I have not been able to fix the vacuum hose, but i took it of the transducer
and there was no vacuum, and i could suck and blow throug it, so i think this is my problem as well!!

 

The vacuum line coming from the fuel rail on the driver's side originates from the back side of the engine. It is a 90' rubber boot approx 5/16 inside diameter attaching to a plastic port on the back side of the intake manifold, about 4 inches right of vehicle center (passenger's side). The port opening faces aft, the boot faces forward. It's hard to see with a flashlight and mirror. If you know someone with skinny arms, they may be able to push it back up into place by reaching between the firewall and the top of the fuel rail. Don't do what I did and go fishing around for the leak until the port comes completely off. I had to remove the injectors and fuel rail to get to it. It's a hell of a design!
Let me know how you make out.

 

I finally found some time to check the vacuum line today!!
Now it's working perfectly again!
Thanks for the instructions and help!
I hope i get the chanse to make it up to you!
Thanks again!

 

go to pg.20 on the link below and you will find a pic of the intake manifold backside and the port for that hose. removing the fuel rail will help a whole lot.

http://store.roushperformance.com/im.../R07000001.pdf

 

Sorry to resurrect this thread but I have a couple of questions on this. I have this same issue on my 04 fx4 supercrew, and the 90 degree boot is completely off of the valve, it's just hanging there. While trying to put it back into place, I checked out the photo that Manny referenced. On my intake, the back cover piece is missing. The clips up top are still there and in good shape, they just aren't clipped into anything. I can put my hand in there a ways and feel around. Does this cover hold the valve in place, thus causing my inability to see it?

Also, with the fuel rail, do I need any special tools to remove the rail from the injectors?

 

does anyone know what this vacuum line goes to? and how to check it without pulling apart the intake manifold or putting a hole in the passenger floor. I don't know if I have this problem but I'm getting P0171 and P0174 (lean on bank 1 and bank 2). Thanks. Have K&N CAI, Flowmaster Exhaust and Superchips tune.

 

You may be getting the lean code due to the CAI without a custom tune for it on a 2004. The 2004s came from the factory in a near lean condition.

 

I just figured out mine the other day. The easiest way is to remove the passenger side fuel rail. If your's is like mine, there's a flexible section in the middle of the rail (the bottom of the 'U'). Just have someone hold the rail up and out of the way and you should be able to reach it unless your hands are huge. As far as the fuel rail goes, you should only need a flat head screw driver to pry the clips off where the injectors meet.

Check out the link that Manny Martinez posted, on page 20 you can see a photo of the hose and the valve it connects to. You won't be able to see it on your truck, but feel your way down using the photo as a reference. You should be able to feel the rods and vacuum lines as you reach in. I put some rubber cement on the inside of the boot on mine so hopefully it will stay on from now on.

 

as for an update on my lean fuel issue P0171 and P0174. Come to find out my PCM needed to reprogrammed (Ford Dealership where I live only charge 45 dollars for it), whoever had my truck before had an aftermarket tuning on it and it was jacking things up big time. I cleaned the MAF Sensor, Reprogrammed the PCM and stuck my old Superchips tuner from my sport trac i used to have and now it runs even better than before. (have no idea what tuner was used before but it wasn't a good one) thanks for all the help everyone.

 

This is just a heads up for a few ppl in this forum I just replace my fuel pump driver module behind the spare tire underneath. Mine was corroded pretty bad split in half.

 

old thread i know... need a picture of the back if the manifold to see what i am looking for and where it goes.. any one have one? plz?