i have a l96 /6l90 swap into 86 square body gmc. everything runs alright but has code. running with e38 / t43 ecm/tcm and harness originally tuned from speartech and still using stock column ignition switch with nothing visibly wrong. also dont know if it has anything to do with it but using stock alternator from the 2017 L96 6.0L engine putting out 14.4 volts. Any ideas welcome