1964fi

I have a ZZ383 GM crate motor with a TPIS mini-ram fuel injection unit with 30lb injectors. It has 3000 miles on it and I have had a problem with spark plug fouling in cylinders 7 & 8 only. All the other cylinders are burning clean. I have a scanner and over time my block learn memory number has remained at 108. Initially my minimum idle adjustment was set at the base setting with the throttle blades completely closed, thus allowing the IAC to regulate more of the air entering the plenum. Assuming the possibility that the majority of my rich issue could be that a sufficient amount of air may not be reaching the back of the plenum at idle, I adjusted the minimum air setting with the throttle blades more open, and then re-adjusted my TPS to reflect engine idle, .47 volts. I have also reduced my fuel pressue in small increments from 45psi to now at 41psi. In addition I have changed from using convential spark plugs to double platinim. My block learn numbers have increased to 118-120 at idle and from 120-130 when driving in a normal fashion. Overall the car runs great. Does anyone have any comments or suggestions on this ? Outside of burning a new prom, is this a reasonable way to correct my problem ?clong@metroelectriccoinc.com