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Dan
Dan, Technician
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98 Mustang GT: 4.6L..Lean..O2 sensors..the mechanics will tell you

Resolved Question:

I have a 98 Mustang GT w/ 4.6L that I am getting Lean condition codes on 3 of 4 O2 sensors. I was told by the person who my daughter bought the car from, that he had put new pipes on it and he had been seeing these codes as well. He said that the mechanics will tell you that the O2 sensors are bad, but they are not. Stating that it has to do with the pipes. Can someone shed some light on his comments and if there is truth to them. How can I test the backpressure to see if it is off and could cause the codes. I don't want to buy 4 new sensors just to find out that that is not the issue.

Thank you in advance for any assistance anyone can give me.

Mark W.
Submitted: 6 years ago.
Category: Ford
Expert:  Dan replied 6 years ago.
What are the exact codes your getting? Thanks
Customer: replied 6 years ago.

Unfortunately do not know the exact codes. The mechanic just said that the 3 of the 4 O2 sensors were 'Stuck' and not coming off of lean condition. He did also mention that the Purge Solenoid needed to be changed out as well. I beleve there was a code for that as well. I will have to get the exact codes from him on Monday.

Expert:  Dan replied 6 years ago.
Ok, get the codes and let me know.....also if you are getting bunch of lean codes the problem is likely a vacuum leak such as a vacuum line, throttle body gasket, or intake gasket. That would be more common then the fuel pump or the oxygen sensors. The chance that all oxygen sensors have failed saying system is leak is very unlikely. Let me know if you have questions, thanks.
Customer: replied 6 years ago.

OK, I had a hard time getting the codes, but here they are:

 

P0155

P0443

P1131

P1132

P1152

P1152

 

Not sure why the P1152 would show up twice, but it did.

 

Right now, the car seems to be jumpy when driving down the road. Also, when at a stop, it will IDL @ around 800 RPM, then jump down to around 200 for a half second then back to 800. Almost acts like it's going to die. This last summer, I had 3 occasions where it was over 100 degrees outside and after about 10-15 minutes of driving, the car started to sputter and loose power like the fuel filter was clogged or something. At the time to codes were 'Lean Condition' (I don't remember the exact codes) from the O2 sensors and I was told it may be a back preasure issue due to the exahust being replaced by the prevous owner. He clained the O2 sensors were not the issue.

 

Again, thank you in advance for your time and advice,

 

Mark W.

Expert:  Dan replied 6 years ago.

Check fuse #8 in the inside fuse panel to see if its blown if so replace. Otherwise it sounds like you may have a a wiring problem. You will need to check for good power and ground on the heater circuit and I think you will find the problem there. If not you will need to go through and inspect each code one by one. The evap purge solenoid may be a unrelated problem if the check engine light was already on before but if it was off and these all came at once then it is likely related. Let me know if you have questions, thanks.

 

P0155 Heated Oxygen Sensor (Bank 2 Sensor 1) Heater Circuit Malfunction

Possible CausesSetting Conditions
  • Check for a low battery voltage condition
  • Check for a disconnected hose to the EGR system module (models with ESM)
  • HO2S connector is damaged (check pins for damage, and for moisture)
  • HO2S heater power (12v) circuit is open (check the fuse in related fuse box)
  • HO2S heater control circuit is open, shorted to ground or shorted to voltage
  • HO2S heater ground circuit is open
  • HO2S heater has failed
  • PCM has failed

P0443 EVAP Canister Purge Solenoid Circuit Malfunction

Possible CausesSetting Conditions
  • EVAP purge solenoid supply circuit is open
  • EVAP purge solenoid control circuit open, shorted to ground
  • EVAP purge solenoid control circuit is shorted to voltage
  • EVAP canister purge solenoid valve has failed
  • PCM has failed

P1131 Lack of HO2S-11 Switching, Sensor Indicates Lean (Bank 1)
Possible CausesSetting Conditions
  • Check for air leaks after the MAF sensor mounting location
  • Check for air leaks in the EGR system and in its related hoses and/or valve
  • Check for air leaks in the PCV system and in its related hoses and/or valve
  • HO2S connector is damaged (check pins for damage, and for moisture)
  • HO2S signal circuit open, shorted to ground, shorted to voltage
  • HO2S has failed (it may be contaminated with fuel, silicone or water)
  • Low fuel pressure or vehicle driven until it was out of fuel
  • Vacuum hoses leaking and/or damaged
P1132 Lack of HO2S-11 Switching, Sensor Indicates Rich (Bank 1)
Possible CausesSetting Conditions
  • Base engine mechanical fault (e.g., compression, valve timing)
  • Check air cleaner element and air cleaner housing for blockage
  • EVAP vapor recovery system has failed (canister full of fuel)
  • Fuel pressure too high, contaminated or leaking fuel injectors
  • HO2S has failed (it may be contaminated with fuel, silicone or water)

 

P1152 Lack of HO2S-21 Switching, Sensor Indicates Rich (Bank 2)
Possible CausesSetting Conditions
  • Base engine mechanical fault (e.g., compression, valve timing)
  • Check air cleaner element and air cleaner housing for blockage
  • EVAP vapor recovery system has failed (canister full of fuel)
  • Fuel pressure too high, contaminated or leaking fuel injectors
  • HO2S has failed (it may be contaminated with fuel, silicone or water)
graphic
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Customer: replied 6 years ago.

I checked fuse slot #8 under the hood and there was no fuse there. I got a couple and when I tried inserting it, it just fell into the slot. This slot is a 'dummy' slot as is 9-12. Is there different wiring configurations for different Mustangs? Slot's # XXXXX have MAXI fusee, but 8-12 do not.

 

98' Ford Mustang GT 4.6l SOHC 5-speed.

 

Any further assistance would be appreciated.

 

Thanks again, Mark.

Expert:  Dan replied 6 years ago.
Give me a minute I"ll look at the diagram again. Thanks
Customer: replied 6 years ago.

I'm so sorry, but I just realized that you said the 'inside' fuse panel. I apologize. I just went out and found the Slot #8 fuse (10 amp) in the inside fuse panel and it checked out good.

 

Sorry about that. My mistake.

Expert:  Dan replied 6 years ago.
Ok, no problem. Next step is to check for good power and grounds at the oxygen sensors. Let me know how that goes or if you have questions, thanks.

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