So today I went to emissions so I can go re register my car. I got there and to my surprise my car passed. I have a catback exhaust with a racingline y-pipe. So after I drove to the DMV, got the car registered. On my drive back home my service engine soon light came on. I stopped at advance auto and got the code reader & P0430 popped up - Cat. System efficiency below threshold bank 2. Soooo are my cats bad? I don't get that sulfer
smell. My mpg is really bad (16/18) but I just thought that was from my tranny acting up (no low end power - thinking it's the torque conv.) well all in all I'm getting a tranny rebuild in a couple weeks so should I just replace the cats and O2 sensors while it's in the shop? And should I be worried about this as I drive the car for the next 2 weeks before I bring it in?

 

Well, continuing to drive could damage all your cats if you have an inefficient burn in the combustion chamber. If it is just the cat that has gone bad, then I would leave it. If, however, the cat is bad due to a combustion issue (02 sensor/plugs/injector) that is causing an improper burn of the fuel, then you need to figure that out to save your other cats from failing as well.

How are your spark plugs? Are they they originals?

 

It could be bad gas. Clear codes, refuel with some good premium gas, and see if it comes back.

 

Well here's an update: I got on the highway yesterday after all this..I was literally on there for about 10-15 mins doing a steady 75-80 and the car started to sputter..the rpms were shooting down and then back up..so I got off the first exit and tried to drive it to my buddys to leave it there and let me tell you this car would barely move..I was at a red light and when it turned green it would barely move with my foot halfway down on the pedal..as it started to inch forward slowly I released the pedal a little and it started to go but it wouldn't go past 2k rpms no matter how much I punched the pedal...just sputtering...somehow I got it to my buddy's house and parked it there and now I'm gonna have to get it towed to the shop..but idk what I'm in for..could it be the tranny finally giving out or is this the cats?

 

The car drives fine in reverse..the spark plugs just got changed not too long ago..I always drive on shell v-power 93 octane gas & I was getting a little gas smell here and there but I didn't think anything of it

 

The car wasn't driven for a couple months till Friday..so idk if that has anything to do with it

 

Well, the car hasn't been driven for a couple of months?

Then you just take it for a rip and you get the code?

Are you using the same fuel that sat in the car for a couple of months?>

 

It sat for 2 months cuz I didnt have it registered. I drive it one or twice around the neighborhood just to take it for a spin. It was fine until after I left emissions. It popped up a little after I left. And no when I was able to drive it i immediately I went and put gas in..shell v- power 93 octane like I always use

 

Sounds like A maf sensor to me ....mine died the same way yours did

 

I was really really nervous cuz I kept thinkin my cold air sucked up some water into the engine it something or that the prefers totally failed and broke apart and got sucked up in the cylinders...I'll know on Friday when I get it towed to my mechanics

 

*precats