98 5.0 sensor dilema

[jimbolin]

I had a MAf sensor go bad and I drove home with it running on what felt like 4 cylinders about 20 miles.I changed out MAF reset computer and it ran great for about 50 miles and the cel came on but still ran great.I took it to autozone to read code and it detected O2 sensors.Not knowing there are 4, I replaced 2 on left side and reset.Still ran great but cel came back on.Had codes read and now it is a 420 code, catalytic converter.The rear sensor on left side was sooty and the front one looked normal. I am going to pull other two in morning,the question is would driving it this short distance in this condition screw up converter?Also if the consensus is to replace converter which ones?There appears to be 2 small on downpipes and 2 clustered together before muffler.

 

[rwenzing]

Running on 4 cylinders for 20 miles could have destroyed one or more of the cats and even damaged the O2 sensors. Running on all 8 cylinders with your current questionnable oxygen sensors is not nearly as dangerous.

FYI - Most trouble codes that mention the oxygen sensor(s) in their descriptions do not necessarily mean that the sensors themselves are bad.

The only cat that is monitored for the P0420 code on your 98 5.0L is the small front cat on the passenger side down pipe.

 

[jimbolin]

With that being said should I try changing the right side o2 sensors or assume that the converters are bad?How do you pin point the problem?Do you change all 4 converters?I hate to keep throwing money at it with out not knowing which componet to change.

 

[rwenzing]

With that being said should I try changing the right side o2 sensors or assume that the converters are bad?How do you pin point the problem?Do you change all 4 converters?I hate to keep throwing money at it with out not knowing which componet to change.

I don't know if any of the cats are damaged or if any of the sensors are bad. I certainly would not replace all 4 converters without a good reason.

Each of the original code numbers would have told you which bank the trouble was on and whether it concerned a front or rear sensor. The PCM compares the switch ratio of the fore and aft sensors on each bank to determine the catalyst efficiency. You need to get the O2 sensors working properly before you condemn the cats.

 

[jimbolin]

Thanks for the input! I am checking the sensors now.