Well I have a 2001 4.0 Wrangler that needs to go through emissions very soon and I am throwing a P420 code and from my understanding that means I need a new catalytic converter. I was about to order a decent high flow magnaflow but when I called a local shop that does my welding and exhaust work in the past to get a quote on labor, I was informed that the rear cat is useless. I infact need 2 cats on my headers replaced since those are the ones that are read by the ecu. I thought those were just pre-cats and the only one that gets read is the rear. Can someone please clear this up for me and point me in the right direction. I need to get this done asap.
Thanks in advance