spark and no spark

Good goin. I would not stop now. Find out why (or recheck!!) the drop in the hot cable. You said it was .6V. That is way too much, and I bet the end connectors are crap.

You can ALSO measure drop "across a connector.

Example........say you want to check the end connector in the trunk for the cable going up front. Of course unless you have a "long" remote starter, this needs two people.

Stab one post right onto the eyelet connector. on the top of the ring end. Stab the other post into the cable proper say, an inch into the cable. There should be almost zero measurable drop