Need Help P0171 & P0174

[rockstar]

Hi,

The check engine light turns on and appear two codes:

P0171 & P0174, do anyone knows what wrong with my truck?

So far I know that it is not the MAF sensor 'cause it is new and the fuel pressure is all raight.

Thanks in advance for your answers

 

[Fordman2]

Ford P0171 and P0174 lean codes are usually caused by an engine vacuum leak. A lean fuel condition may exist if the engine is sucking in too much air and/or the fuel system is not delivering enough fuel. If bad enough, a lean fuel condition may cause lean misfire, a rough idle, hesitation or stumble when accelerating, and/or poor engine performance. Check all the vacuum hoses located near the throttle body for damage.

 

[dorman68]

Ford P0171 and P0174 lean codes are usually caused by an engine vacuum leak. A lean fuel condition may exist if the engine is sucking in too much air and/or the fuel system is not delivering enough fuel. If bad enough, a lean fuel condition may cause lean misfire, a rough idle, hesitation or stumble when accelerating, and/or poor engine performance. Check all the vacuum hoses located near the throttle body for damage.

Fordman is right on the money. My brother's truck had the same issues. There were a few contributors to the trouble codes on his truck, we replaced the following items and all is well.

-Fuel filter
-pcv valve and elbow (elbow was cracked)
-egr dpfe sensor and valve
-upper plenum gaskets.

 

[coffee]

You don't want to run lean for long. A friend of mine builds heads and replaces a lot of sunken valve seats due to a lean condition on 3.0s.

 

[delcogod]

Upper plenum gaskets and intake gasket cured mine, plus allthat other stuff that didn't help but at least its new nw.

 

[mge_1]

I get the same 2 codes on my 95 B4000. Here's what I know so far. Previous owner took out the EGR valve and its now plugged shut. Would this be the case or still vacuum leak or any of the mentioned above? Please advise?

 

[Earl43P]

See Post #2

and read

http://www.explorerforum.com/forums/showthread.php?t=171819&highlight=intake+gasket

should you find no other external vacuum leak.

 

[mge_1]

See Post #2

and read

http://www.explorerforum.com/forums/showthread.php?t=171819&highlight=intake+gasket

should you find no other external vacuum leak.

Thanks for the info and link. Just saw that the fuel filter is installed incorrectly. Pointier side is facing the gas tank. Should be the other way around right? And I'll check for vacuum leaks too and clean MAF.