I have a 2001 Lightning and i keep getting codes P0171 & 174 for lean bank 1 & 2. i have cleaned the mass air flow, checked all vacuum hoses like the pcv hose and all others i could see or get to. my vacuum gauge hooked up to it shows 22 in of vacuum at idle. new fuel filter and it runs GREAT w/ no hesitation or rough idle or anything. i dont know if the AEM Brute force intake has anything to do with it but i doubt it, everything is tight between the mass air and the throttle body. i've ruled everything out i can think of except for the intake gaskets and i dont want to spend 150 on gaskets and have the code still come back. Anyone have any suggestions or had the same problem as me?

 

I just had the same codes in my 03 Cobra. The solution was a new EGR valve.

 

hmmm, ill be sure and check that. i was thinking more about it and i checked my LT fuel trims and they are maxed at idle (25%) but cruising down the road they stay around 15%, i have noticed the light usually only comes on at idle (no matter cold or hot). Also every once in a while sitting still i just notice ever so slightly a possible miss or two at idle, but you really have to be trying to notice it. I also have heard a lot about the ford DPFE sensors but i dont have the proper equipment to view the DPFE data to test it or under what conditions the DPFE even affects the engines performance (idle, highway,??) Ill try to do some more checking.

 

The AEM bruteforce it the likely suspect as it caused the same problem on my truck, reason being is that it is a 98mm tube instead of the stock 90mm. This causes the maf voltage to read lower, and conversly less fuel is mixed in, then the o2 sensors read the lean condition, and when they reach a certain threashold of adding more and more fuel you get the lean codes.

You will have to have a custom tune made for that AEM intake, or switch back to the stock maf.

Try putting the stock maf back on, disconnect the battery cables for 20 mins or so and then see if the code comes back, which it probably wont.

 

please let me know what it was lol i have an 02 lightning that i just bought and its doin the same thing i took it to ford to have them scan it and they told me it might be a couple vaccum lines leaking and the injectors cleaned so i sprayed all vaccum lines with carb cleaner and the idle didnt change so its not that and the injectors are new so the guy i bought it from told me anyway but they wanted to charge me 450 for that i figured id check into it myself the only other thing i could think of is maybe the guy before me put too small of injectors in it i have no clue i dont wanna buy new ones cus thats alot of money even an egr valve like the guy with the cobra is 65 dollars thats alot to spend not knowin its the right thing any help would do thanks

 

I had this very same issue on my '02 Harley F-150. I had the JLP ram air intake on it and the IAT sensor had fallen out of its grommet, so it wasn't reading the incoming air temp correctly!

 

well, i finally figured it out. on mine it did end up being the aem brute force intake. because the aem tube was 98mm vs the stock maf housing being 90mm, it jacked with the mass air flow sensor causing the readings to make it think it was running lean. i tried using a 90mm tube to test it with and it cured my problem. so even tho aem says its quick and easy, theres more to it than that, to make the intake work correctly there would have to be a maf calibration.

 

Yesterday I finally got my Volant CAI from UPS and I was a little to excited when I opened the box and saw all my cool stuff that I ahd ordered. Well,,,, during the install I was anything but attentive throughout the procedure to say the least. It took my less than an hour to install but it should have taken me longer if I was paying attention.

I created code P0171 by not getting the breather hose attached properly to the valve cover of the snorkel on the CAI. I ended up modifing the original factory setup and so far no codes. All I did was buy a PCV elbow from the help section of my auto parts store along with a 3 inch section of 1/4 vacuum hose and the goop glue I already had.

Install the factory breather assembly on the valve cover and note the postion of the other end near the CAI. Cut off the factory fitting and insert about 1/2 inch of the 1/4 vaccum tube on the end that you just removed. It will be a very tight fit but this is what you want. When that is done insert the PCV elbow onto the vaccum tubing and align it to fit the CAI fitting. Check your alignment on everything and smear some GOOP around all the connections. I wrapped mine in electrical tape just to be on the safe side.

Install fitting and finish things off wtih a small hose clamp and that is it. I have uploaded pictures in my album of the completed fitting.

 

i fixed mine too it was the vaccum lines from the pcv valve assembly that were leakin the slightest bit i bought this kit on rpmoutlet.com it kinda upgrades the whole assembly its called a better oil seperator kit it says it reduces the amount of oil goin into the intake too

 

I know this subject has been beat to death but I Finally fixed my truck! I used someone’s post on here for the lean codes and tested the voltage and ohms on mass air flow, idol air control valve and egr pressure sensor. I then changed my fuel filter before realizing that the pcv hose on the back of the block was my problem. There is a way to test this to see if it’s your problem. spray either behind your supper charger or Simply lean over your truck with it running and move the hose that goes from right over the passenger side valve cover to the back of the intake manifold. You will hear a change in the hissing intake sound or disconnect it and see if it will suck your thumb tight to the hole. When I say disconnect it I’m talking about right at the junction over the passenger side valve cover. If you think you might have this problem just remove your passenger side fuel rail and disconnect your upper pcv hoses. Anyone with an 8mm socket or wrench can do this. Make sure the truck is completely cold, and release the fuel pressure using the schader valve on the passenger side fuel rail. Once your pull the fuel rail out of the way you will barely have enough room for your long and skinny arm to fit in there. You will be leaving your injectors in place just move the fuel rail. I have posted a link that from "Maxpower" he has a post called "intercooler cleaning ford lightning" in the picture you can see where the vacuum hose connects to the back of the intake manifold. It is one of the last pictures where the lower intake manifold is shown with oil puddle up in the bottom. This might help you understand where this "troublesome 90 degree elbow" is located. My lightning has 66k miles on it and this elbow looked like someone put a fire cracker in it. After fixing the elbow with one right off the advanced auto help isle for $2.69 my truck runs like a champ.
Intercooler cleaning
https://www.f150online.com/forums/li...ow.html <br />
Oh and I’m not an English major so I’m sure there are plenty of errors in my Wright up..

 

well my link didn't work but if your just go to google and type in " Intercooler cleaning ford lightning" it will take you to f150.net