I Just Failed Smog In California

[L.A.X]

Just failed smog on my 1991 Ex Eddie B. I need a beer and some help. I passed the Evap test. Here are my numbers

HC(PPM) CO(%) NO(PPM)
max allowed mine max mine max mine

15mph 83 17 0.68 0.09 699 743


25mph 69 15 0.87 0.10 601 709


PASS PASS FAIL


So the test shows I have high NOX. What do I need to fix or replace? Car was at operating temp when tested. Filled with 91 octane. Left running during the wait for a test. New plugs, wires, oil change, stock airbox.

Smog tech said its possibly the cats. Any truth and do I have one or two cats?

Thanks

 

[DoraThe_Explorer]

From my general understanding it is the result of high combustion chamber temperatures. This could be because of a vacuum leak, dirty MAF sensor, clogged cat, etc…

Someone else should be able to go into more detail then myself.

 

[Jason94sport]

699 743
601 709

It's not by much...that sucks

 

[L.A.X]

Just recently cleaned MAF before test. All vacuum lines are connected. My truck in non egr