f250 codes

[Thomas Varley]

I have a 03 f250 super duty 5.4. 4x2 it is running code p0174 and pending code p1131 I replaced maf sensor and o2 sensors Are only a few months old. It idles rough I checked vacuum lines but didn't see anything. Any ideas????????? Thanks Tom

 

[Mike Dziubina]

hmmm...I posted a response to this but it looks like it is not showing up...I tried posting that I would post this on another site for you.



anways, here is one response I got from someone else...



rear PCV hose? I have seen them crack in the rear of the engine. Can you check fuel trims?

 

[Mike Dziubina]

was also told to check the spark plugs, fuel filter.



how many miles?

 

[Steve McKellop]

This is the possible sources of both codes.



P0171

Air Measurement System :

MAF sensor (contaminated, damaged, malfunctioning, etc.)

Fuel System:

Fuel pressure regulator (leaking, malfunctioning, etc.).

Fuel filter plugged, dirty.

Fuel pump (weak, check valve leaking, etc.).

Leaking/contaminated fuel injectors.

Low fuel pressure or running out of fuel.

EVAP canister purge valve leaking (when canister is "clean").

Fuel supply line restricted.

Fuel rail pressure sensor (incorrect reading).

Air Induction System:

Air leaks after the MAF.

Vacuum leaks.

PCV system (leak, valve stuck open, etc.)

Improperly seated engine oil dipstick.

Air induction turbulence due to incorrect air filter.

Exhaust System

Exhaust leaks before or near the HO2Ss (exhaust manifold gasket, mating gaskets, etc.).

EGR System:

EGR valve tube/gasket leak

EVR solenoid vacuum leak

Secondary Air Injection:

Damaged/malfunctioning secondary air injection system (mechanically stuck valve).





P1131

Electrical:

Short to VPWR in harness or HO2S

Water in harness connector

Open/Shorted HO2S circuit

Corrosion or poor mating terminals and wiring

Damaged HO2S

Damaged PCM

Fuel System:

Excessive fuel pressure

Leaking/contaminated fuel injectors

Leaking fuel pressure regulator

Low fuel pressure or running out of fuel

Vapor recovery system

Induction System:

Air leaks after the MAF

Vacuum Leaks

PCV system

Improperly seated engine oil dipstick

EGR System:

Leaking gasket

Stuck EGR valve

Leaking diaphragm or EVR

Base Engine:

Oil overfill

Cam timing

Cylinder compression

Exhaust leaks before or near the HO2S(s)

 

[Thomas Varley]

It has about 150000 miles on it

 

[scott degroot]

The 3 most common causes of lean codes on the 5.4 motors are 1) the pcv hose itself where it connects to the intake..it gets soft and then starts sucking air just like the ST does, 2) The actual PCV valve itself. 3) dirty or defective MAF.