dhbpac

Just replaced the original cats w/Bosal aftermarket and had the lambda (post-cat) codes pop up, P1176 & P1177.

I did some searching a few weeks ago, seems like this is due to faster airflow past the rear O2 (post-cat) sensors.

I recall a couple of aftermarket extenders that fix this problem but now can't recall where to find them.

Any help is appreciated!!

all(over)road

https://www.europaparts.com/oxygen-sensor-spacer.html

You are welcome....I run them on mine for the past 15 years.

cu52

I used these spark plug spacers for my piggie pipes in the writeup below. In stock at almost every carpart chain.

B5 ? Removing DP?s to make Piggies (For 6spd) ? S4Mods.com