4.0l sohc. What are the probable causes of DTCs P0133 and P0455?

No code tells you to replace a part , need to do diagnostic's for said code .
P0141 - O2 Heater Circuit (Bank 1, Sensor 2) Description: See the description for DTC P0135. Possible Causes: See the possible causes for DTC P0135. Diagnostic Aids: See the diagnostic aids for DTC P0135. Application Key On Engine Off Key On Engine Running Continuous Memory All GO to Pinpoint Test DW .
DW: Heated Oxygen Sensor (HO2S) DW: Introduction DW1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS) Are DTCs P0040, P0041, P0053, P0054, P0055, P0059, P0060, P0132, P0133, P0135, P0138, P0139, P0141, P0144, P0147, P0152, P0153, P0155, P0158, P0159, P0161, or P1127 present?
Yes No For DTCs P0040 or P0041, GO to DW2 .

For DTCs P0053, P0054, P0055, P0059 or P0060, GO to DW14 .

For DTCs P0132, P0138, P0144, P0152 or P0158, GO to DW20 .

For DTCs P0133 or P0153, GO to DW3 .

For DTCs P0135, P0139, P0141, P0147, P0155, P0159 or P0161, GO to DW9 .

For DTC P1127, GO to DW19 . For all others, GO to Section 4, Diagnostic Trouble Code (DTC) Charts and Descriptions .
DW9 DTCS P0135, P0139, P0141, P0147, P0155, P0159 OR P0161: CHECK FOR A SOURCE OF POTENTIAL HO2S CONTAMINATION

• Investigate the following items as potential sources of HO2S contamination:
  • use of unapproved silicon sealers
  • fuel contaminated by silicon additives
  • excessive oil consumption
  • glycol leaking internally in the engine
  • lead-contaminated fuel
  • short drive cycles in cold weather
  • use of unapproved cleaning agents

Is a concern present?
Yes No REPAIR the source of the contamination.

CHANGE the engine oil and oil filter.

RESET the keep alive memory (KAM). REFER to Section 2, Resetting The Keep Alive Memory (KAM) .

REPEAT the self-test. GO to DW10 .

Ford Explorer 4 0L V6 SOHC P0171 P0174 Lean Codes Common Cause

Harmonic balancer may be bad .

Could be fuel line leak or evaporative.#455.

These codes all relate to fuel. As for the steering stiffening up, it shouldn't stiffen up if not used for a while. Check your tyre pressures, the tightness of the steering pump belt and level of fluid in the steering pump. If those are all fine, then a trip to your local workshop may be necessary.

Hi,, yws, it seems it is an interference engine. See link below for ford forums
Is 4 0L SOHC V6 an Interference Engine Ford Truck Enthusiasts Forums

Smoke testing for codes P0171 P0174 - YouTube

? 5:48
www.youtube.com/watch?v=kZsqEfP-5zM
Jan 18, 2011 - Uploaded by realfixesrealfast Smoke testing for codes P0171 P0174 .... I have a 1995 ford mustang gt 5.0 and it keeps having a Fault code 176 pop up. ....Ford Explorer P0174 code intake air leak check engine light by froggy - Duration: 16:11. by froggy ...

how about a PO133 ,,,should be the first in system

Schematic
The Oxygen Sensor 1 (O2S-1) is an electrical source that responds to oxygen content in the exhaust manifold. When the sensor reaches approximately 316°C (600°F), it produces a voltage based on the difference in oxygen between the atmosphere and exhaust gas. The PCM sends a bias voltage (391-491 mV) on the signal line which is pulled up through high resistance. When the O2S-1 is cold, it produces no voltage and has extremely high internal resistance. The internal resistance of the sensor is much greater than the resistance of the bias pull-up resistor. However, when the sensor heats up, it produces voltage that overrides the bias voltage. This voltage is read by the PCM to determine a rich/lean O2S-1 signal used to adjust injector pulse width. Under normal conditions, low sensor voltage means high oxygen content/lean air-fuel mixture and vice versa. Normal sensor readings will fluctuate between 10 mV and 999 mV DTC P0133 sets when the O2S-1 signal rich to lean or lean to rich average response time is too slow.

DTC PARAMETERS
DTC P0133 will set if the average response time of the LEAN to RICH switches is greater than 125 ms or the average response time of the RICH to LEAN switches is greater than 156 ms for 100 seconds when:
^ Engine speed is between 1500 and 3200 RPM
^ Loop status is closed
^ Calculated air flow is greater than 7 gm/s
^ Commanded air/fuel ratio is 14.7 to 1
^ No cam, CKP, ECT, EGR, EVAP purge solenoid, fuel trim, IAT, MAP misfire, system voltage or TP sensor DTCs have been set.

DTC P0133 diagnostic runs continuously once the once the above conditions have been met.

DTC P0133 is a type B DTC.

DIAGNOSTIC AIDS
Possible causes of DTC P0133:
^ An intermittent connection or corrosion in the O2S-1 harness connector can set this DTC. Use Scan tool to monitor O2S-1 voltage with engine running at normal operating temperature while wiggling the signal and ground wire. Make sure the sensor is tight.
^ The most probable cause for DTC P0133 is contamination. Check for obvious contamination (oil, fuel or engine coolant) by removing sensor. Identify and correct the cause of the contamination if contaminated. Replace the O2S-1.
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Ford Explorer 4 0L V6 SOHC P0171 P0174 Lean Codes Common Cause

P1131 bank 1 indicates the fuel/air ratio is correcting rich for an overly lean condition.
Diagnostic Trouble Codes (DTCs) P0133 and P0153 indicates the response rate of the upstream HO2S(s) is below some calibrated window. The test measures the HO2S amplitude and output frequency. This is accomplished by superimposing a 1.5 to 2.5 Hz square wave over Lambse. The HO2S switching is monitored during this time to see if the calibration limit is met. P0133 is also bank 1.
Although these codes could be caused by several things such as vacuum leaks,fuel contamination,exhaust leaks,miss-fires,etc. Since it is localized on only bank one I would replace that front(upper in the exhaust to back cylinder head) 02 sensor and see if that did not correct my concern.