'87 Runner 22re 4x4
Couple hundred miles ago installed a Denso o2 sensor. Now I'm getting a code 5. Just reinstalled my EGR with new oem modulator. Cleaned carbon out of the rest and the valve is working. The truck runs rough with the sensor pluged in around 2700 rpm when I unplug the sensor it runs smooth as silk. All this after the truck is at normal operating temp. What is causing this sensor to go bad so quickly ? Also, when I pulled it out its very clean

 

How did you clean the carbon out? Use Seafoam or equivalent? Lots of smoke or goop from oils/cleaners/etc. can permanently damage an O2 sensor. Also, double check you don't have any wire breaks/shorts in the wire leading from the O2 sensor back to the wiring harness/ECU.

 

One more thing, when starting from a cold start, should there be higher rpm than my normal 750 rpm. If so, that is another problem for me.

 

Cold idle is adjustable; is usually around 1200-1800 rpm, depending on how cold & what it's set at.

 

Where is the adjustment at for the cold idle?