I put about 3000 miles a year at the most on my Z and for the second year in a row it failed emissions testing and I drove the car 15 miles on the highway to get it warmed up for the test. It failed HC's. My scanmaster at idle shows BLM's ranging from 112-108 for both sides. Block learn is "long term correction" ? does my car need to be driven more often for the correction to get closer to 128 ?

 

Which "cells" are showing those BLM values? If they are the idle and low load cells, they are probabaly fully developed and correct. It only takes a few minutes for the PCM to stabilize them. In some of the higher load/higher RPM cells, it can take a couple of weeks for the engine to operate long enough under those conditions to stabilize the BLM's. Since the BLM's start at 128, and the amount of driving you have done has driven them all the way down to 112-108, there's not much that additional driving is going to do except possible try and drive them even lower.

Do you ever pull the cable off the battery when you are not driving the car? That will reset the BLM's to 128. The fact that they are approaching 108 in some cases means ite probably trying to correct for a very severe "rich" condition, and that would be a cause for high HC's.

 

How many miles on the car? Your O2 sensors will cause the car to run rich as they age, you may be due for new sensors.