P0171 & P0174 codes

[KeithRich]

Hi guys,
Im having a problem with my sport trac and after googling a bit i found this site.

What happen:
wife borrowed the truck and when she returned home she said it was running hot. I took the truck around back , while the truck was still running i opened the radiator cap and started adding water from the hose to the radiator. Well this didn't go so well as the thermostat housing immediately cracked and started spewing water all over the place. It was then that i noticed the check engine light had come on. I waited for the truck too cool down before i finished filling up the radiator and promptly took it to a repair shop. They replaced the upper and lower thermostat housings .

They told me that the truck was also throwing (P0171 & P0174) codes and was skipping on 3 cylinders. They changed the plugs and wires on the 3 cylinders that were skipping and replaced the coil pack . However the truck was still sending codes.

The truck is hard to start and when it does start it have great difficulty idling until the truck warms up. It has a very noticeable loss of power when pulling off and on the top end. I have not noticed any white smoke coming from the exhaust pipe or water in the oil pan.

The problem im having is that my truck is throwing 2 codes . (P0171 and P0174).
From every thing ive read this is a very common issue with the sport trac's.

What I have done:
replaced fuel filter.
removed and cleaned the MAF.
removed and cleaned the IAC.
removed and cleaned the EGR.
replaced the DPFE sensor. (it was melted)
replaced pcv.
removed and check for cracks in the pcv hose elbo's.
replaced the intake gaskets.

If someone couple point me in a direction i have not though of it would be greatly appreciated.

(edit)
Finished putting the intake back on with new gaskets. No noticeable change in engine performance. still hard to start and still has loss of power.
Could anyone offer any further suggestions on what i can try ?

Thanks,
Keith

 

[swshawaii]

removed and check for cracks in the pcv hose elbo's.

Did you remove and inspect the UNDERSIDE of the PCV elbow? (Job 2 Only)

http://www.explorerforum.com/forums/showthread.php?t=314670

 

[KeithRich]

I removed and plugged one end of each elbo and put the other end under pressure. No air escaped. There are no cracks in either elbo.

 

[swshawaii]

Do you have an aftermarket ignition coil? (Screamin' Demon)

 

[KeithRich]

OEM Coil.

 

[swshawaii]

I have not changed the intake gaskets.

Seems you've covered all the bases, may be time to replace the intake gaskets.
Did you spray carb cleaner or similar around them and listen for a speed change?

 

[KeithRich]

I did not .

 

[KeithRich]

bump.

any advice would be greatly appreciated.

Thanks.

 

[waskly]

intake gaskets?

fuel pressure, or fuel pressure regulator?

or cats clogged.

 

[Jeffbethandkidz]

Low compression from the overheated piston rings after it was severely overheated. The newer piston rings are low tension to decrease friction and increase fuel economy...downside is they do not like to be overheated. Perform a compression test across all 6 cylinders and see if it is low.

 

[KeithRich]

Thanks , ill get right on that.

 

[FSTMIKE]

Hello all,
I love this site. You all have a wealth of information that cannot be found anywhere else. I am chasing the infamous P0171 and P0174 codes. I have done most all of the listed tasks to correct this issue. My symptoms are a little different than most that I've seen posted. I have a 2001 (8/2000) Explorer XLS (4 door) vin E (4.0. SOHC). It runs perfect, once it starts. Lately it takes up to 4-5 attempts to get started. I replaced the upper and lower intake manifold gaskets about 2 weeks ago and there was a noticeable difference in the performance (no IAC chatter at idle. It's new as well). My PCV layout has the dual lines that attach to both sides of the upper intake plenum and the single line that attaches at the back of the block under the intake manifold. Today I will remove the intake, once again to inspect the PCV connection (the PCV valve and upper lines are new).
I also found one of the lines for the purge valve was disconnected (at the front of the block from previous troubleshooting.)
My feeling is that the combination of the 2 codes indicate a vacuum leak that is common to both banks.
If anyone has any other suggestions, I would greatly appreciate it.
Thank you.

 

[410Fortune]

both banks are lean and you have eliminated intake air leaks as a possibility
check fuel pressure