took off cat.. throwing codes all over. why?

[brisndl1]

2g eagle 420a
ok... i took off my cat and ran straight pipe to the muffler. at first everything was great! good sound and great performance gains(o.5 sec decrease in 0 to 60). but then it started to throw codes. first came 21, 02 sensor, wich i knew would come. but then after a few days i checked it again just to be safe and now i'm worried. heres what i get when i key dance.
12
21 02 sen
21 02 sen
31 egr
32. evap
first off, why code 21 twice? what did taking off my cat do to throw these other codes and what should i do to fix it. the car still runs great but its starting to sputter alittle when i let off the gas, and smoke a little on the heavy side, but like i said it still runs great.

 

[98gsspy]

Because you have emmissons....


If you have a street car keep that cat on, your car is illegal. I bet the car very loud and there are much better mods for you to do.

Also in this forum we usally compare hp not 0-60 times. There are too many variables that go in to getting 0-60 times so they are a very inaccurate base to judge your car. None of us have dynos at the house so as long as the car feels faster to you than great!

 

[turbodsm_125]

like 98gsspy said, its all about emissions. 2g cars that are after 95 have the ob2 system and it is very temramental when it come to emissions stuff, especially if there is an o2 sensor after where you car should be. do your self a favor and get a high flow cat and a cat back exhaust for the car instead.

 

[starsthensun]

make your own o2 eliminator and keep the cat off.

http://www.dsmtuners.com/forums/art...making-your-own-rear-o2-bypass-simulator.html

or

http://www.vfaq.com/mods/O2bypass.html

It will get rid of your rear o2 sensor code.