Hey Lexus People,

I have a Lexus 1999 GS300 and I'm looking to replace the headers all the way down to the mid-pipe with an OBX front exhaust on eBay http://cgi.ebay.com/ebaymotors/OBX-E...ht_2731wt_1025 and I recently had an check engine light code of 0456 bad catalyst and I'm checking to see that if I change out seeing as this system has 4 O2 sensor holes and the cat is deleted I shouldn't have that code throwed again with this new exhaust should I?

Thanks for all advice in advance

 

There's a SEARCH function on the site that works quite well. you should familiarized yourself with this function for the future, your first look-up is free.

Welcome to CL

DIY header install for GS300 *WITH PICS*
https://www.clublexus.com/forums/per...with-pics.html

 

The obx setup will not eliminate any codes you already have, and it will also cause PO420 and PO430 codes. Your first two pre-cat O2 sensors must be installed and working properly still, if you have a bad one now, replace it. The two post-cat sensors you will need to simulate or de-foul them. If you de-foul them the sensors must be already working properly, if you simulate them you can remove those two completely.

There is much previous info on this like mentioned above, if you search for it..