I've been thinking about this more and I'm pretty sure it won't be a problem with your cats. However, I would recommend pulling out your air/fuel sensor, the one in front of the cat, and swapping sides...This will tell you if it is a problem with the sensor or not.

Also, take a close look around all of your connections and make sure the intake is still sealed. If you have a leak around the intake it can cause this code.

 

Stillen G3, Test Pipes & FI Catback and still not lean enough to trigger CEL

Something is definitely wrong

 

i will swap the sensor and see and will report it here

 

Be VERY careful trying to take the sensors out because they can be a huge pain in the @$$. Plenty of people have stripped the threading on them and had to replace both of them at $170 a pop from the stealership. If you're not familiar, I would have a trustworthy mechanic do it.

 

okay this is some days after.
I went to local mechanic and they reset my ECU. i've been driving since now but when it's very cold outside, engine check light is on. i am not sure if cold weather causes the main problem but it seems to be because of that. and it went away when it got warmer yesterday. any problem with any intake reported yet?

 

I just got a dyno done last Wednesday and my A/F was around 12-13 and I was told that was good. I have the Gen3 and MXP.

 

any good dyno place in norther NJ? im in bergen county