2000 3.8 intermintate stall and ruff running

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#2
Anytime a DTC code call out a "circuit Malfunction" it means that something sooooo basic is wrong at the electrical circuit level that the PCM is unable to perform any useful diagnosis. Think:
  • Wiring: short, open, ground fault, stray voltage.
  • connector
  • sensor
  • PCM
If this were my car I would start with a through visual inspection of the car's wiring harness to the O2 sensors. My thought is the P11xx codes are "red herrings" and should be ignored. The DTC that should be addresses first are the "circuit malfunction" codes.

Do you have an ODB2 scanner that is capable of monitoring operational data? If so it would be handy to know what the O2 sensor voltage is doing over time. I suspect it's "flat line".

Here's some information on an affordable Windows based ODB2 scanner. This is a full function unit with two way communications and full graphing.

ForScan ODB2 scanner w ELM327 USB
https://www.stangnet.com/mustang-forums/resources/forscan-odb2-scanner-w-elm327-usb.57/

I recommend starting EVERY electrical trouble shooting session with a through review of the battery and charging system. It is very possible for a stall issue to be cause by something as simple as a bad battery or loose connection. Don't miss this chance for an easy win (or at least make your trouble shooting easier).

Howto perform charging system voltage drop test
https://www.stangnet.com/mustang-fo...perform-charging-system-voltage-drop-test.56/

>>From Ford service manual.
P0141 - HO2S Sensor Circuit Malfunction (HO2S-12)
See DTC P0135
P0161 - HO2S Sensor Circuit Malfunction (HO2S-22
See DTC P0135

P0135 - HO2S Sensor Circuit Malfunction (HO2S-11)
During testing the HO2S Heaters are checked for opens/shorts and excessive current draw. The test fails when current draw exceeds a calibrated limit and/or an open or short is detected.
  • Short to VPWR in harness or HO2S.
  • Water in harness connector.
  • Open VPWR circuit.
  • Open GND circuit.
  • Low battery voltage.
  • Corrosion or poor mating terminals and wiring
  • Damaged HO2S heater.
  • Damaged PCM.

P1151 - Lack of HO2S-21 Switch, Sensor Indicates Lean
See Possible Causes for DTC P1130
P1130 - Lack of HO2S-11 Switch, Fuel Trim at Limit
  • Electrical:
    • Short to VPWR in harness or HO2S
    • Water in harness connector
    • Open/Shorted HO2S circuit
    • Corrosion or poor mating terminals and wiring
    • Damaged HO2S
    • Damaged PCM
  • Fuel System:
    • Excessive fuel pressure
    • Leaking/contaminated fuel injectors
    • Leaking fuel pressure regulator
    • Low fuel pressure or running out of fuel
    • Vapor recovery system
  • Induction System:
    • Air leaks after the MAF
    • Vacuum Leaks
    • PCV system
    • Improperly seated engine oil dipstick
  • EGR System:
    • Leaking gasket
    • Stuck EGR valve
    • Leaking diaphragm or EVR
  • Base Engine:
    • Oil overfill
    • Cam timing
    • Cylinder compression
    • Exhaust leaks before or near the HO2S(s)
 
Last edited:
#3
wmburns said:
Anytime a DTC code call out a "circuit Malfunction" it means that something sooooo basic is wrong at the electrical circuit level that the PCM is unable to perform any useful diagnosis. Think:
  • Wiring: short, open, ground fault, stray voltage.
  • connector
  • sensor
  • PCM
If this were my car I would start with a through visual inspection of the car's wiring harness to the O2 sensors. My thought is the P11xx codes are "red herrings" and should be ignored. The DTC that should be addresses first are the "circuit malfunction" codes.

Do you have an ODB2 scanner that is capable of monitoring operational data? If so it would be handy to know what the O2 sensor voltage is doing over time. I suspect it's "flat line".

Here's some information on an affordable Windows based ODB2 scanner. This is a full function unit with two way communications and full graphing.

ForScan ODB2 scanner w ELM327 USB
https://www.stangnet.com/mustang-forums/resources/forscan-odb2-scanner-w-elm327-usb.57/

I recommend starting EVERY electrical trouble shooting session with a through review of the battery and charging system. It is very possible for a stall issue to be cause by something as simple as a bad battery or loose connection. Don't miss this chance for an easy win (or at least make your trouble shooting easier).

Howto perform charging system voltage drop test
https://www.stangnet.com/mustang-fo...perform-charging-system-voltage-drop-test.56/

>>From Ford service manual.
P0141 - HO2S Sensor Circuit Malfunction (HO2S-12)
See DTC P0135
P0161 - HO2S Sensor Circuit Malfunction (HO2S-22
See DTC P0135

P0135 - HO2S Sensor Circuit Malfunction (HO2S-11)
During testing the HO2S Heaters are checked for opens/shorts and excessive current draw. The test fails when current draw exceeds a calibrated limit and/or an open or short is detected.
  • Short to VPWR in harness or HO2S.
  • Water in harness connector.
  • Open VPWR circuit.
  • Open GND circuit.
  • Low battery voltage.
  • Corrosion or poor mating terminals and wiring
  • Damaged HO2S heater.
  • Damaged PCM.

P1151 - Lack of HO2S-21 Switch, Sensor Indicates Lean
See Possible Causes for DTC P1130
P1130 - Lack of HO2S-11 Switch, Fuel Trim at Limit
  • Electrical:
    • Short to VPWR in harness or HO2S
    • Water in harness connector
    • Open/Shorted HO2S circuit
    • Corrosion or poor mating terminals and wiring
    • Damaged HO2S
    • Damaged PCM
  • Fuel System:
    • Excessive fuel pressure
    • Leaking/contaminated fuel injectors
    • Leaking fuel pressure regulator
    • Low fuel pressure or running out of fuel
    • Vapor recovery system
  • Induction System:
    • Air leaks after the MAF
    • Vacuum Leaks
    • PCV system
    • Improperly seated engine oil dipstick
  • EGR System:
    • Leaking gasket
    • Stuck EGR valve
    • Leaking diaphragm or EVR
  • Base Engine:
    • Oil overfill
    • Cam timing
    • Cylinder compression
    • Exhaust leaks before or near the HO2S(s)
Click to expand...
Sorry for the late reply but I'm running open headers and I assumed them didnt make that big of a deal seeing how old the car is but it could be causing this?
 
#4
dominator said:
Sorry for the late reply but I'm running open headers and I assumed them didnt make that big of a deal seeing how old the car is but it could be causing this?
Click to expand...
Where EXACTLY are the headers open in relation to the O2 sensors before or after?

If after the O2 sensor, it seems more likely that the problem is due to wiring damage caused by exhaust heat. Regardless, I would be concerned about the hot exhaust damaging the wiring Or the wiring harness touching the hot exhaust at any point.
 
#5
wmburns said:
Where EXACTLY are the headers open in relation to the O2 sensors before or after?

If after the O2 sensor, it seems more likely that the problem is due to wiring damage caused by exhaust heat. Regardless, I would be concerned about the hot exhaust damaging the wiring Or the wiring harness touching the hot exhaust at any point.
Click to expand...
After bank 1 and 2 sensor one they end bout 2 or 3 inches before sensor 2 on each side and sensor 1 is plugged in on each side
 
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