Just got word today.
My upper and lower intake gaskets were shot, dry rotted and leaking. One way he noticed right off that this was a problem... he saw a small amount ( just a couple drops ) of coolant in one of my spark plug holes...on top of the plug itself. He said that is a good sign of a leak from the intake.
He said it was very minor but would cause the ses light to activate. The cold temps played a part in when my ses light would come on, due to the gasket material being brittle cold and heating up at idle.

Once he got down to them, he was glad we decided to change them....bad shape

This is a job I could have probably undertaken in the spring or summer, but just having a car port and 5" of snow on the ground with a high of 35 degrees today makes me glad I paid him.

Total cost was $400 for parts and labor.

So,
Wookie... anything over 100k miles, you might want to consider the intake gaskets. Upper and lower.

 

GREAT I have heard about that as well everyone around me wants like $600 to do intake gaskets I am having my truck looked at tomorrow. Like you I'm tired of throwing parts at it!!! I have had the smoke test done TWO months ago and the intake gaskets were fine. At that time I replaced the PCV valve and the hose that connects it to the TB. I am wondering if that hose that has the fuel filter looking thing that connects to the inlet hose before the throttle body on the intake if that is bad or plugged up somehow? I also keep hearing about the IAC and the throttle positon sensor could be bad as well. If the IAC was bad I should have a rough idle right? Well my truck idles smooth as can be. It just uses a TON of gas! I hope its not injectors! I am way low on $$ right now b/c things are slow at my work. I am usually pretty good at fixing my own vehicles but this CONSTANT problem has got me stumped and I am going crazy trying to figure out just what the hell is the problem!! I just wish a code came up as " XYZ part is bad and needs to be replaced!!"

 

I understand completely.

I wished that the pcm would point out a specific cause / defective part also. Unfortunately for us backyard mechanics, we do not have the means to aquire a Ford scan tool. Im not talking about a $80 code reader from autozone either. Ford Techs use a scan tool that data logs everything so they can tell if a part is functioning within its designed limits. This tool costs well over $6,000 from what I have heard


I have 37 miles on mine now with no ses light. I think if it pops back up on me, Im just gonna jump out of the gdamn truck at 50mph on the freeway and take my chances.

Good luck with it bro and yell when you find it.

 

Mikiedoo, I read you posting today and went Your fix may very will be what it takes to fix my 174 and 171 System too Lean codes. No vacuum leaks in hoses or PVC system can be found. When I first got the truck last summer it would lose a small amount of coolant each week. I could not find the leak, hoses, radiator, water pump and heater core all were ok. After putting in some stop leak the coolant leak stopped. But the intermittent 174 and 171 codes continue.
I will be taking a close look at the intake manifold gaskets.

 

I have been looking for data logging scan tools and believe it or not, Amazon has the same ones that Autozone carry for about half the cost. Less than $200 in some cases. I am still investigating to see if these do what we want them to do. Made by the same people that make code readers. Who would have thought Amazon?

 

I have Diagtech software that loads into my palm pilot that does more than clear codes. It reads all of the Ford codes for my truck. It reads all the pids for the; PCM, ABS, GEM, Hybrid Cluster etc. It also has bi-directional control. Unfortunately they went out of business so I cannot do any of the CAN trucks. My next toy will be this: http://www.autoenginuity.com/products.html

 

Wookie when you had the smoke test done was the motor even a little bit warm? I know on my V-6 I would get the "leaks" when it was cold but after everything heated it would kinda-sorta seal back up.

Sounds like the gaskets might be the next step, or at least another smoke test with the motor stone cold.

Hang in there man you'll get it!

 

I have had the smoke test done cold and warm same results.

 

I just thought of somthing-I don't hear a slight hiss when I undo the gas cap-could that be related to these codes? Or somthing about the EVAP system be malfuntioning as well? I have replaced my gas cap a few weeks ago.

 

Most likely, no and no.

Have you read the freeze-frame data in accordance with the previously referenced TSBs?

 

I have a 2003 Harley Davidson 100th edition Supercharged F-150 Supercab that is now showing the dreaded PO171/174 codes. I can't see that rear elbow because of the supercharger. Has anyone done this on a supercharged model?

It is going to be a pain to do. I cleaned the Throttle bodies, Mass Air Sensor, repositioned the air horn. There are 2 vacuum lines that connect to the lower side of the air horn between the throttle body and the maf. One of these lines just fall off whenever it is snapped into place. I'll start there and see about that egr.

Any suggestions would be appreciated.

 

Insert crazed mans laugh ( AHAHAHAHAHAAAAAHHHHAAHAHAHHH )

My SES light is back as well !!!!!

Just dropped it back off at the mechanics shop. Updates coming in a day or two.
Supertech,
Join the po171 / 74 club. Im actually thinking about having a custom tee shirt printed up...

That says... PO171 / PO174 gang

 

How many of you guys that have 0171 and 0174 codes that won't go away have mods, like an aftermarket intake or any exhaust mods?

 

Mine is a completely factory engine, no mods. Just a flowmaster weld - in on the exhaust side.

 

Put me down for a shirt in 3XL tall

I only have a drop in K&N filter the rest is bone stock.