88 CRX high NOx at 15mph, low at 25mph

[sixto]

I'm helping a friend register a new to him 88 Honda CRX. It failed a smog pre-test today. Looking for some insight (information, not a hybrid vehicle).

How do people fit in a CRX? I'm smaller than the average person and I hit my head and elbows constantly in the CRX. I have to make old man sounds to get in and out. The friend who's getting this car is taller and older than me

Some notes on my Calif smog check experience - A 450SEL with a loose valve guide letting oil pour into a cylinder passed. A Toyota that idled as well with 3 plug wires as with 4 passed. A Mitsubishi with a sporadic EGR temp sensor check engine light passed. A CRX that runs beautifully fails. Must be a Honda thing.

Here's the gist (measurement/allowable):

15mph - 1913 rpm
================

CO2 = 14.9%
O2 = 0.0%
HC = 11/147
CO = 0.03%/0.88%
NO = 1290/889 <-- FAIL

25mph - 2168 rpm
================

CO2 = 14.8%
O2 = 0.1%
HC = 18/122
CO = 0.06%/0.78%
NO = 396/828

IIRC high NO means EGR isn't working properly. But why would it fail miserably in the 15 mph test and pass comfortably in the 25 mph test? Is this another Honda thing? Will cleaning the EGR valve and passages fix this?

Thanks,
Sixto