2001 explorer sport, 4.0L, sohc, v6/86,000miles/ 0171, 0174

Ford has changed the way their engine gaskets are made to correct their 0171, 0174 problems, but whether or not your engine's intake gaskets are leaking or not wll have to be tested to see. Watch your fuel trims when driving and see where they are at. Maf are a big problem with fords as well. Watch the fuel trims and see if you can find the intake leak using choke cleaner. When choke cleaner hits a leak, the fuel trims will immediately react by going negative double digits or high single digits. RE read the posts and it's all been said before.

exhaust manifold leak? I think you mean intake manifold leak, as for what generation of engine controller you have it's irrelevant. The codes and the causes are generic to all makes and models! A K&N will bugger a MAF up on a FORD or a GM, as will intake gasket leaks, fuel pressure being too low, etc! If you have K&N style air filter remove it, throw it away, clean the oil from it off the MAF and clear the codes and see if it remedies it! A easier check for a MAF problem is drive the truck with it unplugged and see what the po171 and po174 codes do, if they stay gone then the MAF is likely bad. Doing this will generate a MAF circuit code but it helps narrow your choices. Again check the forums for Fords with this set of codes and follow those recommendations and keep us postted please on what you find

You are correct, i mis-typed when i was doing the orig. post, i did mean the intake manifold. As far as the air filter, i have the basic fram airfilter in it, it is a little dirty, and could probably stand to be replaced. Ive also cleaned the MAF sensor using sensor cleaner. I used my scanner code reader to clear the codess out and see what happens.. thanks for the help and ideas so far

Let us know what happens and what the result is. With 0171, 4 it's unlikely that an air filter will cause it. I suspect you'll have a reset.

Ok, so i cleared the codes and unplugged the MAF sensor and went driving awhile and here is what i got when the check engine light came on 0113 and 0102. I think those are th codes for the MAF being unplugged but no 0171,4 codes. So im guessing i may be looking at a bad MAF unit.

It's a fair guess!

HI ¡ You should first ceck the MAF sensor and their wires and voltage and ground supply.. These wonna be an easier first check, when u already checked these, inspect all the exhaust sytem, starting from the exhaust manifold and finishing at all your down pipes around the catalytic (check for exhaust leaks).. Also I want to know that, if the Maf sensor was making a code before u noticed the other codes? or the Maf code is a new recently code ? when you erased the codes, didn´t you erased a code that you don´t noticed, (like the MAF) ???? How often are u getting the MAF code ? Because maybe the only problem of the lean condition is only because of the MAF, but actually you have to check all the stuff mentioned to be sure about... ¡¡¡

The MAF codes came up in response to the idea a few posts up about unplugging the MAF sensor, and seeing what codes appear. The codes that appeared with the MAF unplugged were the 0113 and the 0102, but the 0171,4 codes did not appear. 171,4 were the only codes that have appeared until the unplugging of the MAF.

Ok, so here is what i have now. I hooked up my scanner cleared out all the codes that were stored after the MAF experiment. After a little driving, the CEL came on. Hooked up the scanner and pulled the freeze frame data, and here is what i got: Trouble COde-0171 RPM-1554 Calc Load 69.4 Coolant-189 LT FTRM1-3.1 ST FTRM1-28.1 LTFTRM2-2.3 STFTRM2-18.8 Speed was 0 Fuel System 1-Closed Im guessing the data was captured on start up judging from the RPM and lack of speed. I also found out that the airfilter from FRAM that i had in there was an oiled filter designed for trucks/suv's etc. I replaced that today with the basic filter, non-oiled. ANy feedback on the info posted would be greatly appreciated. Thank you once again.

okay so the MAF is replaced or is that still you old MAF?

Old MAF

So you don't think it's the MAF? Have the intake gaskets smoke testted when the engine is cold!

Im leaning towards the MAF, just havent had time to go and get a replacement, and wanted to do some other testing before i replaced it.

well the smoke test would be your other testing as would fuel pressure, egr operation etc!

Ive done a little bit more testing, in the free time ive had here lately. I hooked up the scanner i had a went for a 10 mile drive with my father watching what readings we were getting while driving. One thing we noticed when we were doing normal driving, the fuel trim levels seemed to be in normal range, (or so i think), and when we came to a stop at a light or something, the fuel trim levels went into negative. What shoulkd the normal fuel trim levels be be roughly? Does anyone know where i can find a good picture of the intake manifold online or the engine in general? What does somoke testing involve? I found what i think is the intake manifold and it looks like it will be a pain in the butt to get to. Thanks again for your help. Ill keep you updated when i have the time to.

what kind of numbers positive and negative. like at a steady cruise and idle? A smoke test involves pressurizing the intake with a chemical smoke and watching where it leaks from to pinpoint the vaccum leaks! Again you're going to need to bite the bullet and try a new MAF or take it in for testting! A 10 mile road test with a scan tool is not going to be the magic bullet if you're unsure how to interpret the data it's giving you!

Problem solved, i had done all the checking of the vacumn lines and stuff or so i thought, was changing oil today and decided to remove the plastic cover on top of the throttle body area, and found a vacumn line that had a tear,break, whatever you want to callit in it. It was located in a 90 degree elbow area that attached to a plastic tube on the Left side of the engine (looking at it, standing in front of the engine) the tube ran down the side of the enginethen around to the back and plugged back in the back right part of the engine. Had to buy the whole piece from Ford. after all that has been fixed, everyhtuing is running well, fuel trims numbers hold steady now insteads of jumping around.