How to cure Cel/Mil from removing cat with Non-Fouler

V
2002 Mazda Protege ES 2.0
Update: The CEL came on the next morning when immediately upon starting my car. I'm not sure why it's not working, I did everything correct. But it sounds like the things to check are, 1) Is there a exhaust leak 2) Was the hole drilled big enough. It did feel like I had to really cram the sensor in the non-fouler to get the threads to connect. Could this be the problem? Not enough room in the non-fouler? Thanks.
 
V
2K2 P5
Update: The CEL came on the next morning when immediately upon starting my car. I'm not sure why it's not working, I did everything correct. But it sounds like the things to check are, 1) Is there a exhaust leak 2) Was the hole drilled big enough. It did feel like I had to really cram the sensor in the non-fouler to get the threads to connect. Could this be the problem? Not enough room in the non-fouler? Thanks.
Check what the code is. This fix works for P0421 caused by failure of the precat but you may have something else going on.

Always make sure your ignition coils and spark plugs are good. Running with bad coils or plugs will give you a misfire code which is associated with this problem.
 
V
2002 Mazda Protege ES 2.0
Check what the code is. This fix works for P0421 caused by failure of the precat but you may have something else going on.

Always make sure your ignition coils and spark plugs are good. Running with bad coils or plugs will give you a misfire code which is associated with this problem.
I ran the codes and I'm now getting P0140 and P0037, it was P0421 before I installed the non-fouler. So now it looks like the tight fitting non-fouler might causing an error or there's a wiring problem.
 
V
2002 Mazda Protege5
Sorry to resurrect an old post, but, the pictures aren't working for me. from the 02 sensor to the bung does it go, o2 sensor w/ original washer, big hole, gasket, little hole gasket bung?
 
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