Question on error code P0171. HELP!
I have been batteling with P0171 since three days after I bought the car. It has 167k miles on it.
I have replaced the following:
Spark Plugs (with bosch single tip autozone type ones)
Oxygen Sensors (with universal ones)
Mass Air Sensor
Catalytic Converter
....
Now I took it to a guy a few weeks ago that said those spark plugs are crap and you need the Denso OEM plugs or better (iridium kind, NGK). I didn't give much thought to it since the car was running smooth. He also said that with universal oxygen sensors that when the car says it is running lean, it is actually running rich (that would explain my mpg drop).
Toyota dealer said the aftermarket catalytic converter (DEC direct fit) will always throw a code (despite what everyone else says).
I have changed out the MASF with no difference. Same codes.
and last night it gave me four other codes saying:
Oxygen sensor slow response B1S1
Oxygen sensor circuit malfunction B1S1
Oxygen sensor slow response B2S1
Oxygen sensor circuit malfunction B2S1
This is the first time I have gotten those four codes so I erased the codes and drove it around a little and looked at my scantool and it said P0171 is pending... and sure enough this morning I got the CEL with only P0171 on it.. so I think the oxygen sensor codes were a one time thing. According to my haynes manual two of those codes can indicate a error in the fuel trim.
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I have checked all vacuum lines and everything else I can check that could cause this and the only thing I have not replaced is the ECT sensor which I do not think is the problem.
I ordered some Denso OEM plugs last night online and will put them in, but my question is can the BOSCH single tip generic type plugs I bought cause this error code ??
Or are my oxygen sensors doing something wrong and I should replace them as well ??
Someone give me some ideas, its driving me crazy.
I have replaced the following:
Spark Plugs (with bosch single tip autozone type ones)
Oxygen Sensors (with universal ones)
Mass Air Sensor
Catalytic Converter
....
Now I took it to a guy a few weeks ago that said those spark plugs are crap and you need the Denso OEM plugs or better (iridium kind, NGK). I didn't give much thought to it since the car was running smooth. He also said that with universal oxygen sensors that when the car says it is running lean, it is actually running rich (that would explain my mpg drop).
Toyota dealer said the aftermarket catalytic converter (DEC direct fit) will always throw a code (despite what everyone else says).
I have changed out the MASF with no difference. Same codes.
and last night it gave me four other codes saying:
Oxygen sensor slow response B1S1
Oxygen sensor circuit malfunction B1S1
Oxygen sensor slow response B2S1
Oxygen sensor circuit malfunction B2S1
This is the first time I have gotten those four codes so I erased the codes and drove it around a little and looked at my scantool and it said P0171 is pending... and sure enough this morning I got the CEL with only P0171 on it.. so I think the oxygen sensor codes were a one time thing. According to my haynes manual two of those codes can indicate a error in the fuel trim.
-----------
I have checked all vacuum lines and everything else I can check that could cause this and the only thing I have not replaced is the ECT sensor which I do not think is the problem.
I ordered some Denso OEM plugs last night online and will put them in, but my question is can the BOSCH single tip generic type plugs I bought cause this error code ??
Or are my oxygen sensors doing something wrong and I should replace them as well ??
Someone give me some ideas, its driving me crazy.
99 Solara SLE V6, Automatic
- user99
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