2002 Ford Windstar Error Code P1131 And P1151

code p 0303 refers to cylinder 3--misfire ===causes among others is --engine mechanical fault
the bang could be a major destruction of the engine

Hope this helps you or future parties of intrest. P1131 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 1 P1151 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 2 I would get under your stang and gently clean outside portion of o2 sensors using a scotch brite. Also if you have so dielectric grease pull electrical connections to o2 sensors clean them and add grease. These trick eliminated the o2 sensor OBD1 codes on my 1987 Ford mustang gt

All these are fuel trim codes and fuel control O2 sensor related codes, you have something that is causing this as all the sensors seldom fail. My advice here is to see a Ford dealer for the diagnostics before any parts are replaced.

P1131-- Lack of HO2S-11 Switch (lean)
P1151--Lack of HO2S-12 Switch (lean)

There are at least 26 possible causes in the
Diagnostic Trouble Code Chart

That isn't going to be a driveway job,
your going to resolve

Lack of upstream heated O2 sensor bank 1 & bank 2. I would first check for broken or corroded wires to both upstream O2 sensors. If no apparent bad wires O2 sensors are bad.

Hi, 1151 is an 02 sensor code, 1131 is also 02 sensor code,
0174 lean condition bank 2, and 0171 is lean bank 1. Either this is in need of a whosale of repairs or you have computer issues, From looking at the codes i would first do a complete tune up, Including wires, And inspect for a vacume leak before replacing any 02 sensors..
Take care

p1151 states lean condition at bank 2

TSB
05-22-6
ISSUE:
Some 2001-2003 F-150, 2004 F-150 Heritage and 2001-2003 E-150/250 vehicles equipped with a 4.2L engine may exhibit the malfunction indicator lamp (MIL) on with diagnostic trouble codes (DTCs) P1131 and/or P1151 (system too lean bank 1 or 2). This condition may be due to leaking isolator bolts/port gaskets in the upper-to-lower intake manifold mounting area. This condition is sometimes intermittent and may not be apparent on a warmed-up engine.


SERVICE PROCEDURE

Perform a self test. If DTC P1131 and/or P1151 are the only codes stored in the powertrain control module (PCM) proceed to Step 2. If any additional DTCs are present, follow normal diagnostic procedures found in the PC/ED Manual.

Remove the upper intake and replace only the port gaskets (9H486) and isolator bolt assemblies (9S479). The new isolator bolt assemblies use a rubber material that is green in color, do not install the old isolator bolt assemblies with the black rubber material. Do not replace any other intake parts or gaskets.
While the upper intake manifold is removed, check the exhaust gas recirculation (EGR) orifices that are pressed into each primary port of the lower intake manifold. If any of the orifices are plugged with soot, clean and unplug them with a pick and solvent.

PART NUMBER PART NAME
1L3Z-9H486-AA Port Gasket
3F2Z-9S479-AA Isolator Bolt

Change plugs, and Mass Air Flow sensor. This should do the trick

Try to pin point, (if not already) what the other codes are for. How does the truck run while idling and driving. Also, if the code for one sensor is showing then it's best to go ahead and replace it - it may be bad due to another issue (or code that has shown up as well) and chances are, you'll need to replace the second (if equipped) O2 sensor.