Was about to get my inspection finally, riding on an almost expired R. CEL comes back on for a different problem than original, system too lean and bank 1 o2 sensor no voltage. The threads on the aftermarket y pipe were always sketchy and I always had the o2 sensor about 75% threaded in (stupid, i know). It worked but now I want to fix the threads before changing the sensor. Does anyone know the thread size on for the bank 1 o2 sensor on the y pipe? I think it's the same as bank 2. Thanks alot, its appreciated.

 

so if i am understanding everything correctly you have an o2 sensor that is shot and the threads on your y are bad. If this is the case i would go and pick up a new sensor and then take it to sears or somewhere like that where you can buy or rent a tap and dye set and you can determine the correct thread size and pitch there instead of guessing.

Both bank 1 and 2 have the same thread size and pitch

 

Those O2 sensor threads are 18x1.5.

 

Thanks alot to both of you guys for the input, I will have to buy the tap asap and get this done..

 

Just rent it unless you think you'll be needing it again.