I ran my car while it was misfiring for about 50 miles. Dumb yeah I know. . I'm getting the SES light and P0420(x3) p0420(x2).After resetting the light it comes on after about a week of driving . Ive heard this could be the cats or o2 sensor. Is there anyway I could check the o2 sensors or cats? If it is the cats could anyone recommend me some HFCs that could possible be the cheaper route?

EDIT: car is running fine just a slight decrease in mpg on the computer . about 1
Has anyone tried cataclean? thinking about running a bottle just for the slight chance

 

I'm getting the same SES, and as with the resetting, it doesn't make a difference.

Subbed for results.

 

It's a very realistic possibility and probably more likely than not that both are dead. They work together and if your cats done, your O2 sensors are right behind it. Take it to a smog shop, bro. Get a coupon out of your pennysaver or something and pay $30 to get it smogged. The numbers that your car spits out are all telling. It'll be cheaper in the long run to see what's bad rather than replace everything you think could be wrong.

Go get some NOx, CO and HC numbers

 

If you drove it that long with a misfire, the cats are toast.

 

Go to any good shop and get them to use a good scanner on it to check mode6 data, they can tell you if the sensor is bad or its just what the sensor is reading from your engine, also did you fix the missfire? or did you just now check it, and these are the codes with your missfire