Hi My 96 SE (2.5) has CEL on for codes P0420 and P1131. I've read in other posts that the 1131 code may be due to a vacuum leak, bad HO2 sensor, or dirty MAF. If its due to a bad o2 sensor, which one is it? is it the one on top (near hole for egr tube) or one at the bottom of the precat?
I have a bad main cat that I was going to replace this weekend anyway. It sounds like the honeycomb material inside the main cat is loose. If the main cat is clogged, could this be a culprit for the 420 code since the its near the bank 2 precat?
Any pics on how to inspect/clean the MAF will be much appreciated.
BTW, I got new bank 1&2 precats on ebay for $250, complete with gaskets!
