Originally posted by ZeroHour:
... Is it at all possible that both O2s are bad?


Probably not. I would check for vacuum leaks first (air filter housing, UIM/LIM, exhaust, etc.)

Per 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

P0174 - System Too Lean (Bank 2) Same as DTC P0171, but Bank 2. See Possible Causes for DTC P0171

Last edited by Tony2005; 03/05/06 04:37 AM.
"Always do the cheap and easy ones first." 1996 V6 ATX 96K miles