Well my car failed emission and I am 90% sure it is the O2 sensor. So I go underneath the car to replace it and to my surprise some dumb *** welded in the sensor, now I’m sure that’s not right. To make it worse the sensor that is in there now doesn’t look factor. So what am I to do, grind the thing out?

 

You can add another bung, I did and put in a wideband sensor to monitor A/F ratio.

Just determine which would be the least painful, both ways will most likly require some exhaust removal.

The extra bung can be bought at most Hi Performance shops.

Good Luck