"Hi My 96 SE (2.5) has CEL on for codes P0420 and P1131."
P0420 Bank 1 Precat (firewall side).
P1311 Bank 1 Upper O2 (firewall side)." near hole for egr tube"

"If the main cat is clogged, could this be a culprit for the 420 code since the its near the bank 2 precat? "
Maybe but usually P0401 and P0402 codes when the cat is clogged.

MAF and Bank 1 Upper O2 sensor removal in Duratec Maintenance FAQ
http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=v6maint&Number=958650&page=0&view=collapsed&sb=5&o=31&fpart=1


MAF sensor
http://www.contour.org/mods/mods.php?s=howto&displayid=36
and
http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=zetecmaint&Number=989728&page=&view=&sb=5&o=&fpart=1&vc=1
and
http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/1b/cb/25/0900823d801bcb25.jsp

CEL codes in Main FAQ
http://www.contour.org/FAQ/FAQ.php?s=probs

Additional Cat and O2 sensor help.
http://www.v8sho.com/SHO/TSB0197HO2SServiceTips.htm

Last edited by Tony2005; 06/08/06 03:53 PM.
"Always do the cheap and easy ones first." 1996 V6 ATX 96K miles