im getting 2 error codes a P0137 and a P0422. Im wondering if anyone had any luck with remedying these error codes in the past and what was the leading cause of them. I recently replaced my rear O2 with a new 4-wire universal, which was good for about 50 miles then these error codes came up. Im wondering if this is a CAT problem or is it more likly shitty universal O2's?

also if its the cat i have the spark plug non-foulers that people have used to fool the computer if they use a test pipe or a hi flow cat.

 

It is more than likely that your cat isn't functioning properly. Here's kind of a little break-down. The first 02 sensor is used to adjust the A/F ratio. The second sensor is used to measure the amount of hydrocarbons that have been filtered by the cat itself. If there isn't a real difference between the amount of carbons measured at the first sensor to the second sensor, it'll throw that code, which means that your cat is probably bad. I'm not too sure if using the non-foulers on a stock cat will do much. I know that when I installed my test-pipe, I had to use them for sure. Honestly, replacing your cat with a high-flow cat (which can get pricey, but if you are in an emission state then you're kinda stuck) or doing a test pipe can net you some good performance gains. I noticed a nice gain after doing mine, spools earlier and quicker, gained more on the lower end. My cat was really really really really bad though. There's some good write-ups here too to do it yourself. Somebody correct me if I'm way off, but that was my understanding of how this whole 02 cat sensor thing works.

 

yeah mass does emisson testing but i believe they only use the OBD reader for post 1996 cars, so in theory a non-fouler on a car with bad cats should pass emisson by fooling the OBD reader