I have a 93 notch with an efi 351w. I have recently started to get some sort of voltage drain at idle and when it does this the engine kind of has a little stumble. pretty consistant issue rpm doesn't seem to change to much think the stumble is more from possible lack of spark power when volts drop. any ideas. just for kicks I have a one wire alternator not to familiar with these so i THOUGHT I would mention that could the regulator in the alternator cause this possibly