ok, for the past 2 weeks I have been fighting with a P0420 - Catalyst System Low Efficiency code. I get 2 at a time (same code) and nothing I've done seems to have kept it away.

What I've done
added fuel stablizer - didn't work

syphoned the tank, replaced the fuel filter, filled up with midgrade from Chevron and added fuel injection cleaner - that lasted about a week

Anyone have any idea's what else I can do? I can't afford a new sensor, or cat so i'm at a loss.

On my 05 Fire, I'm running an AEM CAI, 60mm TB, Pacesetter header, magnaflow cat & custom 2.25 cat back. i've been running that set-up for almost 2 months now and not had a problem untill last week...

Well the way that code is set, is by the differance between the upstream O2 and downstream differances. One simple check would be to, check the voltage coming out of the o2 sensor on the manifold. It should fluctuate between .1 volt and .9 test that first. if its a steady number its not working. Mkae sure the car is up to operating temp when checking it.


Speed costs... How fast ya wanna go??
<a href="http://mywebpages.comcast.net/pj1987">My old cars</a>

read what i wrote on our site rj


its the way the rear o2 is reading your high flow cat