Engine Performance problem
1988 Buick Lesabre 6 cyl Front Wheel Drive Automatic 150000 miles
wont start. No spark at Coil pack. Replaced with no success. No computer code (other than diagnostic 12 ) Check ICm with 12 volt test light at coil pack contacts to Ground. No steady or flicker light. Tried 1997 ICM and coil pack and noted flicker on one terminal and steady on at other under each coil but no spark. I'm assuming different wiring at ICM. Any other ICM ohm or other shade tree test.