ronallen91277

Hey, I'm new to the site, and have done an extensive search for help with my problem, but none of the results are quite the same as my problem. I have an '04 F-150 with the 5.4l and am getting codes p0171, p0174, p2195, p2197. I read out the meaning of all of them and I know I have lean fuel in both banks. The engine runs fine while driving with no issues. It starts to shudder and die about a minute or so after I come to a stop. Hot or cold engine has the same results. Changing out the fuel filter and adding injector cleaner has had minimal results. Cleaning the maf sensor did little to nothing, and I can't find any vacuum leaks. What else could cause this problem? This has been going on for about a week. Thanks in advance for the help.
Ron

Mod (Ret.)

You've done some good homework...kudos to you!

Here's a link addressing the p0171 and p174 codes.

http://www.aa1car.com/library/ford_lean_codes.htm


You've already addressed the MAF, but what about the EGR differential pressure sensor? Acording to the article, this is a common failure on Fords after 60K. Found this information for lean conditions (p0171 , p0174, p02195 and p2197):

"The codes, no matter if they are 171/174/2195/2197, are all the same type reporting codes for excess air entering the intake system and sensor failures themselves.
All the hoses, cracks in the intake manifold, bolts loose, gasket sucked in, air entering the exhaust ahead of the OX sensors is all detected by the O2 sensors and try to richen up fuel injected but can only go so far in corrections..
This goes to the point the motor runs rough from leaness in and not enough fuel to counter the leaness.
There are different procedures to use for leak detection. Some use propane, some use smoke, some use a scanner to watch certain sensor reactions to forced test procedures.
Go over air tube, the air meter, the throttle body and mountings.
Anything that attaches to the intake and could admit air.
Go over intake manifold to block bolts.
At idle, the IAC most likely closes down in response to the 'outlaw' air in trying to get the idle to match the program value, so the converter loads the idle speed down such that the IAC won't correct for it and your giving throttle makes up for it."

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ronallen91277

Thanks for the link,but according to the Haynes manual there is no egr system on the 5.4 liters. I plan on going over the entire truck this weekend to check for any exhaust leaks before the o2 sensors.

ronallen91277

Could bad o2 sensors cause these codes?

04fifty

Did you Figure this out? I have EXACT issue. Please Help if you Can

kevhead75

I would be looking for vacuum leak or air entering the intake after the MAF

04fifty

Yes that is one of the items I have suspected but have searched pretty thorough. Unless its the injector orings or Intake manifold gasket, I havnt found one. After I cleaned the Throttle body by removing air intake plenum and spraying TB cleaner into the the Throttle body and reassembled is when the issue started. I have since replaced the Throttle Body suspecting I might of damaged while cleaning. No dice. Put a new gasket under the TB for good measure after trying it with original. Truck runs fine rolling down the road. At idle it will typically run for a minute or two stumbling around then gives ups and dies. (Was cleaning TB in hopes to cure a slight annoying rough idle...now its for real, dies and throws codes)

05 4x4 Triton

I had a egr differential pressure sensor go out and it threw a p0401 code. My truck had 190k at the time and other than the code it was almost impossible to tell anything was wrong other than the check engine light. After doing some research I found out that the engine runs extremely rich to prevent doing damage to the egr system. The easiest way to test the sensor is to test the in and out voltage.

P.S. That's just if you want to check the sensor.

04fifty

I believe I found the source of my issue. There is a small RED vacuum hose on my 2004 5.4 3v 4x4 truck that comes off the fuel rail pressure sensor on drivers side and loops around back of engine where it plugs into the back of the lower intake. The connection at the back of the intake is a simple 90 boot that fits over a nipple. From the wonderful info on this forum and others I went down the vacuum leak path but searched tirelessly to find it. Finally the can of Carb cleaner spraying behind the motor center left Did give a very slight rev to the motor. Unfortunately I could not reach it to re-install it. (probably should of waited till my wife was available to stick a smaller hand down) but I got impatient. Currently I have removed Intake and cleaned up parts. Today I will install. thinking of cinching a zip tie or the likes to add a bit of friction to the connection on install. When I first began to remove intake I thought you had to take injector rail loose from intake to remove and removed the bolts. Put some pretty good tugs on the injector rail ends to pluck out the injectors...when they didnt roll out I discovered they didnt all need to come out the rail can stay secured to the intake and simply disconnect at fuel feed on drivers side. Now I am contemplating the need to to go ahead and install new o-rings on the injectors as I did hear a light pressure release when I loosened the bolts (note: Remember to either pull injector fuse or tap fuel shutoff switch and depressurize fuel line before disconnecting.) I think this (Red Vacuum Line) MIGHT be an 04 4x4 specific line...but not sure on that. My vehicle has 138k on it.

04fifty

Back together. Codes are gone. That was the deal. One little vacuum tube in an unreachable spot off the the back of the intake. Bought a Fel Pro gasket kit from Orielly's that had new Orings for injectors, water housing left and right, intake gaskets. Fitting the brake booster hose back on was a touch tricky and took some hand squeezing to pull if off, but its doable all from the top. It can be inspected from the right angle to insure connection from the underside of the truck drivers side with a Mag light. Also other tips that may be helpful. Take pics of wire routes when removing intake so when reassembling intake you are sure not to bind up the flap controllers on back of intake.
I would like to say my motor runs smooth as silk, but it doesnt. The hose clearly fixed the codes and the issues of stalling I was having but in P. there is a fine shuttering thats annoying. Hopefully that will fade with some more driving. the motor was pretty gunky on the inside so I used some Deep Creep sea foam and tooth brush while I was in there, it might just take a while for some of that crud to clean out. It is however smooth as silk in gear at idle with AC on or off. I found some picks and info on removal of intake from a Rousch article on the web that helped identify some of this stuff and made the job easier.