I recently had the CEL reset. The code was P0171. Engine fuel:air mixture is too lean. I did some research and found a decent website: http://autorepair.about.com/cs/faqs/l/bl175h.htm

STOOPID question: Where do I start (easiest first)? PVC valve or hose? MAF sensor? Fuel filter?

THANKS!!
Shamun

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Check for air & vacuum leaks

Clean the MAF sensor

Originally posted by shamun:

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...The code was P0171. Engine fuel:air mixture is too lean. ...

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Most times, it is a vacuum leak. Check for air leaks at hoses, gaskets. Spray with carb cleaner, if the idle changes, you found the leak.

Clean MAF sensor.
MAF sensor
http://www.contour.org/mods/mods.php?s=howto&displayid=36
and
http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=zetecmaint&Number=989728&page=&view=&sb=5&o=&fpart=1&vc=1
and
http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/1b/cb/25/0900823d801bcb25.jsp

From TSB,
P0171 - System Too Lean (Bank 1) The Adaptive Fuel Strategy continuously monitors fuel delivery hardware. The code is set when the adaptive fuel tables reach a rich calibrated limit.

Fuel System:
�· Contaminated fuel injectors
�· Low fuel pressure or running out of fuel (fuel pump, filter, fuel supply line restrictions)
�· Vapor recovery system (VMV)

Induction System:
�· MAF contamination
�· Air leaks between the MAF and throttle body
�· Vacuum leaks
�· PCV system concern
�· Improperly seated engine oil dipstick

EGR System:
�· Leaking gasket
�· Stuck EGR valve
�· Leaking diaphragm or EVR

Base Engine:
�· Exhaust leaks before or near the HO2S
�· Secondary air concern

Powertrain Control System:
�· PCM concern