I have 1999 chevy suburban 4x4 5.7. Cranks ok but no spark. Only sparks when you stop cranking it. Test ac voltage at icm to vcm pin B while cranking no voltage. only when stop cranking I would get 1.4v. Test pin Icm to pin 9 c3 at the vcm no short to power nor ground. Need help why this is happing.