CEL on only when driven in City

[Texplorer1998]

Hello All...1st time poster here.

I have a 1998 Explorer, 5.0 and the CEL in on. I had Auto Zone check the codes and it is giving out a Po141 (O2 Sensor, Bank 1, Sensor 1) and P0420 (catalytic converter).

The only thing is the light only comes on when I do alot of city driving. I recently went on a 900 mile round trip and the light went off, so i assumed it was just carbon buildup or whatever it is called only to have the light come back on, again, during city driving.

Anyone have an explanation for this? Would a bad O2 sensor cause the P0420 code? Unfortunately, I need to get it inspected and I am wondering on whether to replace that one sensor (Passenger side, sensor before the converter) and see what happens. I am on a tight budget and want to see the feedback I get from the experts in this forum.

Thank you in advance for any and all replies. God Bless!!

JB

 

[robertoa1a]

You may get several differing opinions on this topic but I am thinking that carbon build-up has reached a critical point. Mine seems to run better after a long trip.

Sometimes running a can of Sea-foam through a vacuum line offers relief. I haven't had to pass emissions in a long time (FL) so I dint know if Auto Zone can tell you if it will pass or not. On tight money, I would try Sea-foam followed by a highway drive with the OD off. I wouldn't do it during traffic because the Sea-foam makes your exhaust smoke like crazy.

 

[Texplorer1998]

Thanks for the reply..I will try and let you know.

JB

 

[Texplorer1998]

I did the sea foam routine today and after I finally located the PCV valve, I removed the PCV valve and poured about 1/3 of the can directly into the hose opening where I removed the valve. I used a funnel and poured a little at a time. I tried to pour enough for the engine to die on its own, but never did. So, I turned engine off, waited about 1/2 hour. After turning engine on...it did smoke, but not that much. I drove it at different speeds for about 20 minutes and some smoke would come out after acceleration, but not much. I am hoping these are the expected results. I did replace the PCV and engine did seem smoother, but not significantly smoother.

I poured the remainder of the can into my gas tank, filled it up and we shall see if these helps...

Now, is it recommended for me to disconnect battery to clear CEL and drive or should I wait and see if CEL goes out by itself?

My neighbor saw me do this and thought I was crazy. He would rather I pour about a cup of auto transmission fluid into my gas tank to clean fuel system?????

Thanks again...

JB