Help reoccuring P0157 codes after changing the O2 sensor after the CAT twice?

[CKENDZIORA]

I have a reoccuring issue with the above code I have changed the o2 sensor after the converter twice in 30 days and cleaned the MAF and intake butterfly also, help??? Engine seems to run fine no miss or power issues, Fuel filter or upper o2 sensor maybe???? I just dont want to willy nilly throw parts at the thing?

Auto zone has been helpful reading the codes for me...

[j cAT]

Originally Posted by CKENDZIORA

I have a reoccuring issue with the above code I have changed the o2 sensor after the converter twice in 30 days and cleaned the MAF and intake butterfly also, help??? Engine seems to run fine no miss or power issues, Fuel filter or upper o2 sensor maybe???? I just dont want to willy nilly throw parts at the thing?

Auto zone has been helpful reading the codes for me...

this could be many things.
first before buying parts you swap the downstream O2 sensors if the dtc does not change you have NO O2 sensor problems...

then because its the passenger side after cat converter O2 sensor giving data the pcm determines to be lean condition , you check for exhaust leaks////broken manifold bolts etc...


then you get a guage and measure the fuel pressures 53-62psi..

then check all wiring to the sensor/connector/pins/and all grounds as the poor grounding can very well cause this..

lastly the intake manifold may have a leak,,which is common ,as the gaskets/manifolds fail...if it is the manifold gasket make sure its not warped,,,,

[CKENDZIORA]

Originally Posted by j cAT

this could be many things.
first before buying parts you swap the downstream O2 sensors if the dtc does not change you have NO O2 sensor problems...

then because its the passenger side after cat converter O2 sensor giving data the pcm determines to be lean condition , you check for exhaust leaks////broken manifold bolts etc...


then you get a guage and measure the fuel pressures 53-62psi..

then check all wiring to the sensor/connector/pins/and all grounds as the poor grounding can very well cause this..

lastly the intake manifold may have a leak,,which is common ,as the gaskets/manifolds fail...if it is the manifold gasket make sure its not warped,,,,

So there is 2 downstream o2 sesnsors then one for each bank? I also noticed a o2 sesnor in the exhaust manifold on the same side under the hood?

[j cAT]

Originally Posted by CKENDZIORA

So there is 2 downstream o2 sesnsors then one for each bank? I also noticed a o2 sesnor in the exhaust manifold on the same side under the hood?

you have 4 O2 sensors. bank 1 is the driver rside....bank 2 is the passenger side of vehicle...

sensor 1 is the upstream O2 sensor ,,,sensor 2 is the down stream O2 sensor..

the sensors upstream of the cat converter send signals that control the fuel mixture, by way of the PCM [computer],,,and keep the vehicle from polluting...the air..


the sensors downstream report the cat converter effeciency at removing pollutants..these do not control anything ,,but you will get a check engine light and you therefore will not pass inspection if required..

So what tests have you done so far ?

[CKENDZIORA]

Originally Posted by j cAT

you have 4 O2 sensors. bank 1 is the driver rside....bank 2 is the passenger side of vehicle...

sensor 1 is the upstream O2 sensor ,,,sensor 2 is the down stream O2 sensor..

the sensors upstream of the cat converter send signals that control the fuel mixture, by way of the PCM [computer],,,and keep the vehicle from polluting...the air..


the sensors downstream report the cat converter effeciency at removing pollutants..these do not control anything ,,but you will get a check engine light and you therefore will not pass inspection if required..

So what tests have you done so far ?

I havent had the time to pursue this yet but were would I get a fuel pressue gauge? Auton zone I assume? I cant tell you when the fuel filter was changed either would that be worth it to try that 1st?

Would spraying carb cleaner at the intake while the truck is running help diagnose the intake manifold?

[j cAT]

Originally Posted by CKENDZIORA

I havent had the time to pursue this yet but were would I get a fuel pressue gauge? Auton zone I assume? I cant tell you when the fuel filter was changed either would that be worth it to try that 1st?

Would spraying carb cleaner at the intake while the truck is running help diagnose the intake manifold?

these engines will suffer damage with carb cleaner,as the materials used are not designed for the chemical...

throttle body cleaner, or propane gas works with no damage..keep chemicals from the electrical wires/connectors.

the fuel pressure guage is sometimes available at auto zone etc...

the fuel filter should be replaced every 30-40,ooomi...
if you do replace it cut thefilter open to see if it was plugged up..