Yup, check the harness going into the coil. There should be 3 wires there for the two plugs that go together to plug into it. They have a habit of corroding.
This is obviously the easiest/cheapest possibility, but I would check it first.
1996 Impala SS - 45K original miles - 5.3 LS swap - Brand new Bilsteins...WHAT A DIFFERENCE!