I thought I remembered a thread awhile ago where someone said that it was a good idea to unhook your MSD ignition box when you were programming your PCM with a laptop. Does anyone else follow this school of thought? And if so, what would be the safest way to go - just unhook the positive lead from where it connects to the battery?

 

No need to disconnect the ignition system. Just make sure that your battery is fully charged and that your laptop has a charged battery and is connected to the wall as well.