Problem with Cats

[Sicilian Medic]

I'm just shy of 90,000 miles on my green monster. I've babied this car for the past few years, as now it's a garage car that I drive 1-2 times a week. About a month ago, I threw a "check engine" light. It was determined that my passenger side catalytic converter was bad. Purchased a new one and had Midas install it with no issues. Today, after I just literally put 4 new tires on this car, the check engine light comes on AGAIN while I am accelerating onto the freeway. Has anyone had experience with bad cats in general? I'm going to take it to Auto Zone tomorrow and have them run the codes. When Brake Masters ran the codes, there were no misfires or anything significant that lead them to believe that something "major" was causing this issue. Thoughts? Ideas?

[Lil' Nasty]

First thought that maybe the other cat went bad. Post up the code when you get it

[Sicilian Medic]

P0420, P0430, P0430 p/r. Cleaned the MAF, took a look at CAI and throttle body which are both clean as a whistle.

[Lil' Nasty]

Originally Posted by Sicilian Medic

P0420, P0430, P0430 p/r. Cleaned the MAF, took a look at CAI and throttle body which are both clean as a whistle.

IMO it's probably a bad sensor or the other cat has failed. did the second set of codes indicate if it was the other bank that threw the codes?

[GamerDude]

Originally Posted by Sicilian Medic

P0420, P0430, P0430 p/r. Cleaned the MAF, took a look at CAI and throttle body which are both clean as a whistle.

My car spits the same codes every once in a while out of the blue and go away on their own after a few drives. As long as your car is running fine, see if it goes away on their own after driving it a few times. A few WOT pulls and a few long drives home does the trick for me

But, being that your car is 7-8 years old and coming near 100,000 miles, have you ever changed the spark plus on your car? Bad plugs can affect your cats. I also hear cheap gas can cause this too. Check if your gas station that you use is on this list www.toptiergas.com/licensedbrands/

[Sicilian Medic]

Changed the plugs less than 5,000 miles ago. So far, my research is leading me in the direction of the following: Checking for any vacuum leaks, replacing the intake manifold gasket and purchasing anti foulers/O2 extenders. This is before I jump on the catalytic converter train again.

[Eddiefuzz]

I get 420 or 430 every time I take a trip more than 100 miles. Just clear it and drive on!