A few people have asked about the O2 sensors and wide open throttle operation...so here's the facts on the OPEN/CLOSED Loop operation :

There are 7 different modes (conditions) that are used (besides Key-ON and Key-Off mode) and here's the list of what sensors are monitors and determine the mode:

(1) Engine Start-Up Mode (OPEN LOOP)
Battery Voltage
Coolant Temp
Crank Position
Intake Air Temp
MAP
MAF
TPS
Starter Motor Relay
Cam Position

(2) Engine Warm-Up Mode (OPEN LOOP)
Battery Voltage
Coolant Temp
Crank Position
Intake Air Temp
MAP
MAF
TPS
Cam Position
Park/Neutral Safety Switch (Automatics Only)

(3) Idle mode (Once at Operating Temp: CLOSED LOOP)
A/C Select (if equipped)
A/C Request (if equipped)
Battery Voltage
Coolant Temp
Crank Position
Intake Air Temp
MAP
MAF
TPS
Cam Position
O2 Sensors
Park/Neutral Safety Switch (Automatics Only)

(4) Cruise Mode (CLOSED LOOP)
A/C Select (if equipped)
A/C Request (if equipped)
Battery Voltage
Coolant Temp
Crank Position
Intake Air Temp
MAP
MAF
TPS
Cam Position
O2 Sensors
Park/Neutral Safety Switch (Automatics Only)

(5) Acceleration Mode (OPEN LOOP)
A/C Select (if equipped)
A/C Request (if equipped)
Battery Voltage
Coolant Temp
Crank Position
Intake Air Temp
MAP
MAF
TPS
Cam Position
Vehicle Speed Sensor
Park/Neutral Safety Switch (Automatics Only)

(6) Deceleration Mode (OPEN LOOP)
A/C Select (if equipped)
A/C Request (if equipped)
Battery Voltage
Coolant Temp
Crank Position
Intake Air Temp
MAP
MAF
TPS
Cam Position
Park/Neutral Safety Switch (Automatics Only)
Vehicle Speed Sensor

(7) Wide Open Throttle - WOT (OPEN LOOP)
Battery Voltage
Coolant Temp
Crank Position
Intake Air Temp
MAP
MAF
TPS
Cam Position

Under conditions 1,2,4,5,6,7...
the O2 Sensor is ignored by the PCM.