Hello all.  I drive a 1998 Chevy Tracker 2 Door.  When I bought it the exhaust was completely rusty along with many other issues.  I replaced the exhaust with a 2.0 pressbent unit with a High Flow Cat.  Performance picked up and so did the PO420 code which is ever present.  I tried the spark plug anti fowlers (2 of them in fact) to space out the Rear 02 and that did not work. 


Any advice on how to defeat that nasty CEL light?

Thank you