Help!!! Code P0172 popped up!!!

[Nelson_00'_Expy]

Can anyone tell me how to fix this code? Or where to start diagnosing? Any help is appreciated!! I have a 2000 Ford Expedition 5.4L

 

[Bedrck47]

P0172 - System to Rich (Bank 1)

The Adaptive Fuel Strategy continuously monitors the fuel delivery hardware. The test fails when the adaptive fuel tables reach a lean calibrated limit.

See Possible Causes for DTC P0171

P0171 - System to Lean (Bank 1)

The Adaptive Fuel Strategy continuously monitors fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit.

For lean and rich DTCs:
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 HO2Ss.

Bank 1 is the passenger side

 

[Bedrck47]

http://www.expeditionforum.com/f42/about-egr-pcv-dpff-evap-iat-tps-maf-23583/#post191356

 

[docraymund]

Yes it means that the O2 sensor detected a rich condition on bank 1 of the engine. That's the left side if you are facing the engine. Causes could be a dirty MAF sensor or dirty air cleaner or a vacuum leak.

 

[Bedrck47]

Yes it means that the O2 sensor detected a rich condition on bank 1 of the engine. That's the left side if you are facing the engine. Causes could be a dirty MAF sensor or dirty air cleaner or a vacuum leak.

WOW didn't I post all of that and more

 

[stamp11127]

Kinda sorta...he just put it in easier to understand terms.

 

[1st_gen_expy]

I had the same code. I was able to just take off the air filter housing and clean the throttle body with throttle body cleaner and put fuel injector clearer in the gas tank and the light went out.

 

[Nelson_00'_Expy]

Thanks for the replies guys! Now i have the codes p0172 and p0175. I also noticed that my expy cranks too long to turn on. I was thinking of changing the fuel pressure regulator but i cant seem to find it. A local mechanic told me he wants to change the fuel pump. What do you guys think?

 

[Flexpedition]

The fuel pressure regulator is cylindrical, bare aluminum/silver in color,attached to the fuel rail on the passenger side of the engine, towards the firewall. Should have a (good working!) vacuum line attached to the top of it.

F150 5.4L example, Expedition should be similar or same:

What pressure readings are you & your mechanic seeing at the fuel rail and/or fuel pump that suggests the regulator or pump is the trouble?

 

[98eb5.4]

Thanks for the replies guys! Now i have the codes p0172 and p0175. I also noticed that my expy cranks too long to turn on. I was thinking of changing the fuel pressure regulator but i cant seem to find it. A local mechanic told me he wants to change the fuel pump. What do you guys think?

i'd wanna know the reason(s) and diagnosis before deciding, otherwise real easy to waste money changing good parts