Emissions Testing....Passing 2500 RPM HC, yet Fails Idle HC test. Help?

[Michael Miller <msmiller_spiritone@domain.elided>]

This smog test will be the end of me.

'88 Spider Grad
65,000 miles
Changed the oil yesterday. (10W40)
Changed all the plugs.
Idle is at 850 RPM.
Took the car into be tested at 185 degrees. (so it was
definitely hot).

The car passes the 2500 RPM HC test at 30ppm (Max
limit is 140ppm).  Yet keeps on failing the Idle HC
test.  I scored a 275ppm. (Max is 120 PPM).

Is my idle too low?  

Should I also replace the Rotor and the CAP?  Or
simply pony up and buy a new CAT.  Yet if it was the
cat...wouldn't I have failed the 2500 RPM HC test as
well?

All help is greatly appreciated. 

Thanks
Mike
'88 Spider
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