Code PO171, PO174 Help

[Lazzman]

On a scale of 1-10 what is the degree of difficulty of this procedure?

I am pretty well skilled at fixing my X but certainly do not want to have it apart and not be able to put it back together.

Also are any special tools needed besides a T-30 Torx bit? Do I absolutely need a torque wrench, as I cannot afford to buy one.

Thanks

 

[peterqb24]

I had the same cold start idle problem, and I replaced all of the items that you did. But, when I had the intakes off to do a seal replacement, I also replaced my ECT (Coolant temp sensor) & the temperature gauge sender that both sit on top of the thermostat housing. I would HIGHLY recommend replacing this housing> The brass nuts that hold the 2 sensors in place will loose their grip inside the housing, and the sensor will just spin and will not seal. You can buy a new housing that has a much smarter sealing system for these sensors. It will also have a new thermostat installed in the housing.
The new ECT should tell your computer that it's friggin' cold outside and the throttle needs to be warned so that it sets to the proper rpm.
Whenever I go to such an extreme repair that involves taking a lot of stuff off of your engine, like intakes, I always replace whatever parts I can that would involve taking the intakes off for a replacement repair. You may also want to replace the timing chain tensioner that is in that same area. More money to spend, but you save tons of labor time.

 

[94explorer2x4]

You have been chasing this for a while have you checked the vac line going to the egr to make sure it is not getting vac all the time mabey a failed egr valve solenoid? Have you checked the intake gaskets bu running water along the intake mounting surfaces while it is running to see if the engine sputters. You mention that you replaced the dpfe sensor why was that?

NATE

 

[danny98explorer]

Wow that was a lot of good reading.
I have like 8 codes that eventually Ill post them up, including Po171, and 174.

 

[Mr. Glen Oaks]

Part # ?

Since I frequently suggest checking vacuum hoses and lines I probably should try and list them. I'll start a list here and eventually generate a thread with photos identifying the listed items.

The photos below will help me list the lines.

View attachment 59873

1. top left: power brake booster

2. top center: PCV valve "T"

3. bottom center: PCV valve "T"

4. bottom left: (splits into three lines with two lines splitting again into two) fuel pressure damper, EGR vacuum regulator, evaporative emission canister purge valve, vacuum reservoir bulb below air filter enclosure

5. center: IAC valve inlet (short flexible hose and rigid tube)

View attachment 59928
6. top center: fuel vapor management valve (T connection with 7 below at front of engine)

7. bottom center: fuel vapor management valve (T connection with 6 above at front of engine)

Hello, thanks for this helpful post. I know this is an old thread but I was wondering if anyone could help with the part # for the P.I.T.A. hard plastic hose that connects the rubber hose assembly underneath this manifold / plenum to the Vapor Canister Purge Valve in front of the Driver side wheel?

 

[dblack1140]

I had the same problem with my explorer two years ago; PO 171, 174, rough idle and poor gas mileage. After about three months and a replaced the MAF, nothing seemed to work.
I mixed half a bottle of glass cleaner with dish soap and sprayed it all over my engine in hopes of finding the leak. I had a vacuum leak. As it was, I had a leak close to my intake manifold, when the car was running you could hear the leak. It cost me $10 to get a new hose. Also, my dad give me this advice, if the car still runs and it's not a danger to you or others, keep running the car. The problem will soon present itself.

Good Luck!

Dblack

 

[parabellum]

I also had codes 171 & 174 also a misfire code come up, wife was driving home and truck stalled. I have replaced fuel pump,fuel filter, spark plugs and wires.Still haven't got it running yet

 

[BrooklynBay]

Check the intake manifold gaskets for vacuum leaks.

 

[darrell milgrim]

Same problems on a 2000 sport trac. Replaced everything and it was fuel vapor vent solenoid on top of gas tank. That controlled fuel pump speed on my system. I was told.No codes since it was reolaced.

 

[scottfab]

Only reason I am coming back to post is that often on this forum I see no final disposition posted. No final out come................anyway.
My son's 2000 Limited had both the 0171 and 0174 codes.
Replaced the upper and lower intake manifold gaskets after trying may other solutions. That was it. leaky gaskets.

 

[rigbyrigz]

Part # ?



Hello, thanks for this helpful post. I know this is an old thread but I was wondering if anyone could help with the part # for the P.I.T.A. hard plastic hose that connects the rubber hose assembly underneath this manifold / plenum to the Vapor Canister Purge Valve in front of the Driver side wheel?

Here in 2021 looking for part numbers for the hoses you have mentioned , including the rubber one that goes to the purge canister under the battery. It might even be the same hose going THRU the Purge valve, then up to intake manifold...

...many hours research and reading still can't find Ford?MM/oem part numbers or name for this hose, for sale anywhere. Did anyone ever answer (or knows?) Thanks. (Not really equipped to ghetto up some nonspecific ordinary vacuum hose of suitable diameter).