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Running very sluggish at times and poor gas mileage

Tiny
ZZF46J
  • MEMBER
  • 2004 FORD MUSTANG
  • 4.6L
  • V8
  • 2WD
  • MANUAL
  • 160,000 MILES
I had all four O2 sensors engine codes on and the car is running very sluggish at times, waste a lot of gas. I have taken it to several mechanic shops and they cannot figure out the problem according to their diagnostic machines, all the tell me it can be the PCM. So my question is, can the PCM cause this issues with car and have all four O2 sensors codes?
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Wednesday, September 19th, 2018 AT 11:38 AM

12 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good afternoon.

Lets back up a bit.

Lets start with the codes? Can you give me a list of the code numbers?

Roy
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Wednesday, September 19th, 2018 AT 11:50 AM
Tiny
ZZF46J
  • MEMBER
  • 7 POSTS
Yes, p0161, p0153, p0141, p2196, p2197, p1000.
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Wednesday, September 19th, 2018 AT 12:07 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Descriptions below. Forget about the 1000. That will go away when the others are fixed.

The PCM is common, but a very expensive guess that may not be correct. All the items listed need to be checked first before going to a PCM.

Roy

161

P0161
Descriptor
Ho2S Sensor Circuit Malfunction (Ho2S-22)
Probable Causes
Ground Circuit Open
Harness or Heated Oxygen Sensor (HO2S) Short to Ignition Switched Power (VPWR)
Heated Oxygen Sensor (HO2S) Heater Damaged
Ignition Switched Power (VPWR) Circuit Open
Low Battery Voltage
Poor Mating Terminals and Wiring or Corrosion
Powertrain Control Module (PCM) Damaged
Vacuum Hose Disconnected On EGR System Module (ESM) Applications
Water in Harness Connector

153

P0153
Descriptor
Ho2S Sensor Circuit Slow Response (Ho2S-21)
Probable Causes
Exhaust Leaks
Heated Oxygen Sensor (HO2S) Contaminated
Heated Oxygen Sensor (HO2S) Deteriorating
Improper Fueling
Inlet Air Leaks
Mass Air flow (MAF) Sensor
Wiring Shorted or Open

141

P0141
Descriptor
Ho2S Sensor Circuit Malfunction (Ho2S-12)
Probable Causes
Ground Circuit Open
Harness or Heated Oxygen Sensor (HO2S) Short to Ignition Switched Power (VPWR)
Heated Oxygen Sensor (HO2S) Heater Damaged
Ignition Switched Power (VPWR) Circuit Open
Low Battery Voltage
Poor Mating Terminals and Wiring or Corrosion
Powertrain Control Module (PCM) Damaged
Vacuum Hose Disconnected On EGR System Module (ESM) Applications
Water in Harness Connector

2196-97

P2197
Descriptor
Lack Of Ho2S-21 Switch, Sensor Indicates Lean
Probable Causes
Air Induction System Leak after the Mass Air Flow (MAF) Sensor
Cam Timing
Cylinder Compression Incorrect
Diaphragm or EGR Vacuum Regulator (EVR) Leaking
Engine Oil Dipstick Incorrectly Seated
Exhaust Gas Recirculation (EGR) Valve Malfunction
Exhaust Leak Before or Near the Heated Oxygen Sensor (HO2S)
Fuel Injectors Leaking and or Contaminated
Fuel Pressure Excessive
Fuel Pressure Low or Insufficient Fuel
Fuel Pressure Regulator Leaking
Gasket Leaking
Harness Short to Ignition Switched Power (VPWR)
Heated Oxygen Sensor (HO2S)
Heated Oxygen Sensor (HO2S) Circuit Open or Shorted
Oil Overfull
Poor Mating Terminals and Wiring or Corrosion
Positive Crankcase Ventilation (PCV) System
Powertrain Control Module (PCM) Damaged
Vacuum Leaks
Vapor Recovery System
Water in Harness Connector
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Wednesday, September 19th, 2018 AT 12:27 PM
Tiny
ZZF46J
  • MEMBER
  • 7 POSTS
I did check some of the items from the list, like I notice there was a leak coming from the EGR valve and I fixed and replace it. So now the car runs a little better than before. The weird thing is that at times when I press on the gas at a stop light the car does accelerate normal and then at other times the car is sluggish to accelerate. I do see that most of the codes list does mention the damage PCM.
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Wednesday, September 19th, 2018 AT 12:36 PM
Tiny
ASEMASTER6371
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Yes, it does, but that does not mean it is the issue. I would not assume it until you do the voltage and harness tests to be sure.

I would also verify fuel pressure.

Roy
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Wednesday, September 19th, 2018 AT 12:38 PM
Tiny
ZZF46J
  • MEMBER
  • 7 POSTS
I do see the diagrams that the PCM does send signal to the four O2 sensors. Could it be that the PCM at times is faulting and that is why the car accelerates good at times and other times it does not and hesitates?
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Wednesday, September 19th, 2018 AT 12:42 PM
Tiny
ZZF46J
  • MEMBER
  • 7 POSTS
Have you seen or heard of all 4 O2 sensor codes on a car? And if so what was the issue? Trying to cut down on what it can be. I have spent some money on mechanic shops and do the diagnostic machine test not cheap and they all tell me it can be different things from the list.
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Wednesday, September 19th, 2018 AT 12:45 PM
Tiny
ASEMASTER6371
  • MECHANIC
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Yes, the PCM controls them all.

One of the common denominators is also wiring harness. That is more common than the PCM. I would be looking hard at that first.

No, all four failing is extremely rare.

Roy
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Wednesday, September 19th, 2018 AT 12:53 PM
Tiny
ZZF46J
  • MEMBER
  • 7 POSTS
Can I check myself for a wire voltage with a voltmeter or does it have to be with a professional? So it is possible that a wire can cause the car to malfunction this way and cause all four sensors code?
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Wednesday, September 19th, 2018 AT 1:00 PM
Tiny
ASEMASTER6371
  • MECHANIC
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You can check this yourself. You need to check for voltages to all four sensors.

It may not be one wire but a whole cluster of them. Look around all the areas where the harness for the sensors go down from the engine compartment and see if it is close to the exhaust and may have damaged the harness.

Roy
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Wednesday, September 19th, 2018 AT 1:06 PM
Tiny
ZZF46J
  • MEMBER
  • 7 POSTS
Do you know the voltage each O2 sensor should put out?
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Wednesday, September 19th, 2018 AT 1:25 PM
Tiny
ASEMASTER6371
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The output needs to be monitored with a scan tool. Most of them range from 0 to 1 volt. The heater side runs on 12 volts.

Roy
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Wednesday, September 19th, 2018 AT 1:36 PM

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