I rencetly got my highflow cat taken out and replaced it with a 3 inch pipe still having both o2 sensors. When i got that done i put in new o2 sensors. when it came off the lift my car had a ruff idle and occasional idle surge. when i drove it, it sputtered for a bit then ran fine. I took it to autozone and pulled P0122 and P1457
Now everytime i drive it the first 2 minutes i drive it it sputters then drives fine and sometimes has a ruff idle

any suggestions?

 

http://www.bigdaddiesgarage.com/straight-cel-fix.html

Try one of these matey, I have a cat replacement pipe on mine and you need to space your post-cat O2 sensor aways from the extra gasses and heat. It fools the ecu into thinking all is fine with your cat and therefore no CEL light

 

...... I dunno what p0122 is buT I would buy a cel fix or make one. They cost around 8-10 bucks to make. As fo the p1457 that's an evap issue that on the canister side I have thi problem also and if u send me a pm with ur cell I'll call u and tell you what to do to fix it. It's not a gas cap error so just pm me ur number an I'll cOl u asap

 

p0122 reads "catalys below efficiency level" on the snap-on scanner diagnostic machine so yeah CEL fix should definately sort that out. I put that link on because this guys are a little more expensive but he makes them out of stainless steel so no rust

 

You guys think it's because the o2 sensor are too close together on the cat?

 

the guy who welded the new high flow put both of them on the high flow instead of one on the header and one on the high flow?

 

Can you post a pic of what your front pipe/manifold setup is like mate?