"Catalyst System Efficiency Below Threshold (Bank 1)"
I've been dealing with this code for quite some time now. When it started I didn't notice any performance issues. My fuel efficiency may have dropped a little, but that's it. I have a CarChip so I configured it to monitor the O2 sensor readings. Both the front and rear sensors were oscillating steadily in about the same pattern. From what I've read, the rear sensor should be pretty steady. Since it wasn't, my catalytic converter was bad. I took it to a shop and had a new cat put on.
The check engine light stayed off for about 5 months and now it's back on. I figured (and hoped) it was a leak or something simple like that, but I took it to a different muffler shop and the guy looked at it and said my cat was going bad (again). Either the new cat that was put on was really crappy, or something with my car is causing the converter to go bad prematurely. He suggested replacing the O2 sensors, but they both appeared to be reading fine when I looked at the CarChip data so I'm not sure if that'd be wasted money.
I've started having performance issues this time around. When accelerating, my engine lacks power and it stutters occasionally. The other day on my drive to work the engine was running really poorly. When the engine was idling it would get down to about 400 RPMs and act like it was about to stall. The check engine light started flashing (before it was just steady) so I read the code and it said cylinder 1 was misfiring. I replaced the spark plugs wires and after that the engine was running perfectly (no stuttering). But the next day the stuttering resumed and the P0420 code came back on a few days later.
I know I'll probably need a new cat since it seems mine's fried again. But does anyone have any idea as to what could be causing it to go bad in the first place? I don't have my log on me, but the spark plugs have been changed fairly recently. Do I need to replace the O2 sensors? Both or just the rear one? Any advice would be greatly appreciated.
Thanks,
Aaron
I've been dealing with this code for quite some time now. When it started I didn't notice any performance issues. My fuel efficiency may have dropped a little, but that's it. I have a CarChip so I configured it to monitor the O2 sensor readings. Both the front and rear sensors were oscillating steadily in about the same pattern. From what I've read, the rear sensor should be pretty steady. Since it wasn't, my catalytic converter was bad. I took it to a shop and had a new cat put on.
The check engine light stayed off for about 5 months and now it's back on. I figured (and hoped) it was a leak or something simple like that, but I took it to a different muffler shop and the guy looked at it and said my cat was going bad (again). Either the new cat that was put on was really crappy, or something with my car is causing the converter to go bad prematurely. He suggested replacing the O2 sensors, but they both appeared to be reading fine when I looked at the CarChip data so I'm not sure if that'd be wasted money.
I've started having performance issues this time around. When accelerating, my engine lacks power and it stutters occasionally. The other day on my drive to work the engine was running really poorly. When the engine was idling it would get down to about 400 RPMs and act like it was about to stall. The check engine light started flashing (before it was just steady) so I read the code and it said cylinder 1 was misfiring. I replaced the spark plugs wires and after that the engine was running perfectly (no stuttering). But the next day the stuttering resumed and the P0420 code came back on a few days later.
I know I'll probably need a new cat since it seems mine's fried again. But does anyone have any idea as to what could be causing it to go bad in the first place? I don't have my log on me, but the spark plugs have been changed fairly recently. Do I need to replace the O2 sensors? Both or just the rear one? Any advice would be greatly appreciated.
Thanks,
Aaron