2003 Ford Focus - P0171

[Fudged Undies]

Anyone have an idea if there is a common problem that throws this code? About 62k on the car, already changed the fuel filter. Below is a list of what the code covers. Wanted to see if there was a MORE common cause for this code. Kinda hoping it's similar to the vacuum elbow like on the trac.





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.

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).

 

[Kevin Palmer]

The above list comes back to a common issue. A running lean condition. Which, is the same issue as well as code number the Trac has when the infamous vacuum elbow breaks on the passengers side on top of the intake.



I would take a very good look to see if you have any vacuum lines that have broken or fallen off their connections...

 

[Fudged Undies]

What I figured Coastie. There's a hose that comes off the back of the valve cover, which I'm wondering if it isn't the same as the elbow.

 

[Fudged Undies]

As an update, since there are a couple of new focii owners, there is a vacuum hose that runs from the rear driver side of the valve cover down to the block, forgot to ask the parts dept for the name so don't know what it's called. However much like on the trac there is an elbow on the hose where it connects to the block that was cracked and somewhat collapsed as well.



A trip to the dealer, $40 later and about 5 minutes and the problem appears to be fixed. Won't know until tonight after the car has been driven a bit but upon start up, there's no more shimmy and shake.

 

[Kevin Palmer]

Nice snag... Glad you found it.

This type of issue can be hard to find sometimes...



Congrats...