Those 171, and 174 is driving me crazy. Does anybody have the part number for the hose on the back of the TB that has two different sizes on each end? Mine is 98' f150, 4x4, screw, 4.6. I've been fighting this thing since the new motor was installed a year and half ago. I do know that I have a problem with the egr tube that comes off the driver's side exhaust manifold. It's rusted pretty badly. I patched it and I think it's not letting air in. I've replaced just about everything on the truck except for the truck itself. That vacuum hose needs to be replaced and I couldn't find a part number for it. So I put a couple of hose clamps on each end to see if that would help. I'm unable to find any kind of a vacuum leak with a couple of cans of brake cleaner. I'm going to make another stab at this CEL problem this weekend along with new brake pads, oil change, and rotate the tires. The truck runs like a champ. Last resort could be removing the bulb from the CEL inside the dash and sell the truck. LOL

 

I have a 2000 F150 4x4 Supercab XL with a 5.4L. I am getting the lone P0174 code. A friend of mine (certified Ford Tech) is going to go over it this weekend and see if we can figure it out. But I am going to try checking that PCV elbow first. That and my spark plugs are about 15,000km overdue, I'll get those replaced aswell.

Will reply with findings.

Update: I tried to reset teh code using my OBDII tool (Equus 1003), but didn't work, so I unplugged the battery, and the code disappeared. Took it for an exhaustive test drive, and it hasn't come back. Maybe I got lucky and it was just some ice in the fuel line.

 

Well, i reset my battery about a week ago...drove it for about 100 miles and the CEL light came back on.. I have to get this fixed today as i live in GA and my birthday is tomorrow and i have to get my tag (you have to have an emmisions test to get your tag). So i will be working on this all night to see if i can get it fixed.

So far i have tried to clean up every hose that i can see, replace spark plugs, oil change, replace air filter, replace all fluids just about and i still don't know what to do...this 2003 4.2ltr is kick my a$$ when it comes to this light.. the truck runs great with no issues at all....really sucks that so many people have had this issue yet not one person has been able to say, "hey i fixed it by doing this........."

 

oh and put in some fuel injector cleaner....still nothing

 

"hey i fixed it by changing the fuel filter!"

Click for link to thread I had a while ago about it.

 

could be that your intake gasket/seals are leaking on bank 2(driver side) is there any exhaust leak? does it have enough fuel pressure? how olds the fuel filter? spark plugs all tight?

 

Actually, I bought my 98, 11/2007 with check engine light on with both those codes. Doing some question asking and some research I found out that it was going to be a pain but a do-able fix. Knowing the previous owner didn't believe in prevent mait. or mait. period, I bought the truck for less than 1/2 of it's book value. Sad thing is, he works as a mechanic at a shop one town over.
Anyway, did the obvious, because it ws long overdue. Changed plugs, air filter, fuel filter, oil change, etc. Checked thoroughly for vacuum leaks everywhere, had a buddy who owns a garage (he did the work by the way, I had no experience with A COP ignition system) turn the CEL off and within a 100 miles both codes came back. I finally joined this forum and let everyone know what I had done and these were the 2 things that were suggested to correct my problem.
(1) Disassembled the MAF sensor from the air cleaner housing and thouroghly cleaned it with CRC Electronics cleaner. (alot of members will suggest you use MAF cleaner, I didn't use that but I am sure it will work.) I reset the PCM with my new Equus scanner and eliminated one of the codes, P0174
(2) The other thing I was instructed to do was to inspect the PCV Assembly from the valve cover all the way back to the TB. I did this and thought that there were no defects. I reset the PCM and 100 + miles later it came back. I rechecked for vacuum leaks and found none. Said the heck with it and bought a NEW PCV assembly from Ford for $28.00, installed it and to this date, I have not had that or any other code come back.
Maybe I was fortunate, lucky, Blessed, I don't know, but these 2 last service proceedures corrected my problem.

Good luck with it.

TJKinCNY

 

What doesn't suck is a forum like this to give you some kind of direction when lost -

Those are pretty easy codes to over come, - specially on a 6. What needs to checked has been mentioned over and over again many times in this forum. I'll give yuh a tip on those vac lines tho - Dip them in Lacquer thinner before you plug them in - they won't leak.

Any of the above could fix the problem.

 

OK, So looking over just about everything on here.....This is what i have gone through.

1) Took off the MAF sensor and cleaned it up really, really good...like..really good.

2) Put it back on, reset the codes.

3) Decided that the Emissions test would be like, hey your good to go. Little did i know...I failed the Emissions test because it said that my cpu wasn't ready.

4) I have been driving around for a few days and today the light came back on.

5) Fuel Filter...now this guy is a pain.. i havn't replaced it in some time if at all since i have had the truck. I went to my local AutoZone and got the filter.asked the guy if i need any special tool as i remember the one on my mustand was a pain in the rear to remove...he said na..just pull it off.

6) After 1/2 and my head smelling like gas i decided to give up on the fuel filter.

7) Got the tool from a friend that looks like an X and can remove the brackets that are holding down the fuel filter (i've heard bad things about this tool and that it sucks..but hey i should be able to get it to work).

8) Tomorrow i'm going to replace the filter...Reset my codes and see what that does in the next few days.

As of right now i'm riding around with an un-registered truck because i can't get it registed because of a CEL that really has nothing to do with the smog my truck puts out...or well i don't think it does. Ill keep you all updated.

 

the trick on the X tool after finding the right size, is forcing the hose all the way forward over the tool, then slowly wiggle the tool and hose backwards off of the filter

 

Fuel filter change is a good thing but I don't think it is your problem, but DO change it anyway. I don't know much about your V6 but can run over to my Brother-inlaws and look at his wife's explorer to help you along if I have to. I have to tune that vehicle up for them anyway (a bit overdue). Have you checked for vacuum leaks everywhere and did you pull and check out your PCV assembly yet.

 

Bobby, I am also in GA and my birthday is in about a week. I've been doing the "dance" with the battery and waiting for the drive cycle to complete. No dice. I need to find a solution, too.

 

Well, i got the fuel filter replaced. The X tool had two diffrent sides to it, worked like a charm. Still though, CEL. Next stop is MAF Sensor. Looking online it's running for 135$ thats with a core price of 35$ i figured this weekend i will be running out to autozone to pickup the part( get it ordered first).

So once again..thank you F150 for creating a code that could really mean that everything is going to die on your truck unless you replace just about everything.


Keep ya posted, good luck on the emissions, i am using my driving time spairly right now as i still have no registered tag...go Georgia!

 

Just replaced the Fuel Filter, from the looks of the pressure ( i forgot to remove the little "bike pump of a nozzle" on the engine block to remove the pressure, got alot of gas when i first tried, didn't have the X tool so had to sit back and punt). ECL = ON

Replaced all sparkplugs, snug as can be, replaced wires aswell. Exhaust leak is possible, after i replace the maf and restart the computer (remove red battery lead) i am just going to take it to a ford dealer and see what he can do for me....

 

You had the MAF tested and it was deemed worthy of replacement or is this a money tossing venture?

You can reset the ECU by pulling the ECM fuse in the underhood fuse box. Easy enough.

For future reference, you can release fuel pressure by pulling the fuel pump relay (in that same underhood box) and cranking the engine dry for a few seconds.

Also, looking at whatever you want to will not substitute for an actual fuel pressure gauge and fuel pressure test.

Some of these F-truck exhaust manifolds are known to leak, so I would investigate that further. But, that is one heck of a leak on both banks.