Emissions help

[Jim Wright]

I received the dreaded failure today, and a quick search of the  
archives didn't help a lot, because of the varying numbers.  Here's  
my story:

High speed test:
Avg RPMs:  2195
HC(PPM): 187 (Pass)
CO%: 0.55 (Pass)
CO2%: 13.9
O2%: 1.2
NOx(PPM): 0.00
Dilution%: 14.5

Idle test:

Avg RPMs: 804
HC(PPM): 307 (Fail)
CO%: 0.73 (Pass)
CO2%: 11.4
O2%: 4.3
NOx(PPM): 0.00
Dilution%: 12.1


HC and CO are all that needs to pass here, I'm assuming that NOx  
wasn't measured since I have zero for both sets of data.  This is for  
a '91 SE-R, K&N filter, cat, exhaust, etc.  O2 sensor is a few years  
old, car has been running 87 octane gas, as much as I hate doing  
that, the good stuff is too damn much for regular driving.  K&N  
filter recently cleaned and oiled, platinum plugs w/about 20k miles,  
cap/rotor/wires about the same age, fuel filter replaced about 10k ago.

The cat on the car is at least 6 years old, I can't remember for  
sure, O2 sensor is at least that old.  I've got 2 weeks to get this  
passed, cheaper suggestions appreciated.  ;)


Jim