[axsaxoman]

first suggestion is to change all main power leads and earth leads --could be just old age bad connections seen a few main battery earth leads that look fine but internal connections are corroded enough not to pass big current --so you end up with ecu voltage dropping on cold start --put a volt meter on something like ecu main power and see what it drops to under cold start cranking
could even be a bad starter thats just drawing too much current