I'm swapping my engine on 05 TL 6 speed. Just took cats off n they are shot. I got an aftermarket exhaust that came with precat deletes that I wasn't going to use because I thought it would throw a code. Would they throw a code?

 

if the Precat deletes did not come with defoulers, then yes. it will throw a code.
a defouler is sort of a spacer.
it spaces the 02 sensor from the exhaust stream, if spaced correctly, the 02 sensor will act normally and not throw a code.
if not spaced correctly and 02 sensor sits in un-filtered exhaust stream, car will throw a code

 

Thank you! I bought the last tsudo high flow cats I could find. I already dumped so much money into this car that I wasn't springing for the rv6 ones.