hello guys well

here the long story short. I bought this car like year ago, everything was pretty and 100% stock no mods"

like most people firts upgrade" short or cold air intake hearder or full exhaust

in my case I just put a axle back muffler for some noise, short ram air intake. And cheap hearder.

now 3 months later after installed the header I got 3 codes yeah 3 fu@$)& codes p0155 p0430 p0420

i research a little and here is what I found and to be hones no much to search it's really obvious

"sometimes the code hints at something upstream or downstream being the culprit and not actually the obvious.

cat codes can be thrown because of o2 sensors or a bad cat but you have to think about what causes the cat to fail in the first place.... running too rich or burning oil.

the cat can also deteriorate from running too rich and having hotter exhaust temps at the cat for long periods of time. if you added a cold air intake, header and better flowing exhaust you could be running super lean and it would only take a few weeks/months to kill the cat and o2's from running lean. i've had seen a few that the metal cage melted and all that was left is the ceramic left.

if you are running anything other than a bone stock swap you need to put money towards getting a chipped p28 and getting it tuned. running rich/lean for too long can do all kinds of bad stuff from killing your ringlands to cracking a sleave.

now some cuestion I just got the donut oem gasket for the downpipe to cat, and I just wating for the manifold gasket, so here is the cuestion the donut gasket need to goo all way down ?

 

Nope, just that far.