Buick Repair Questions? Ask a Mechanic for Answers ASAP
You swapped the coil packs and it runs on all cylinders now or still misses and your miss didn't move?
Most likely this is going to be caused by a bad ICM. That's the thin computer that the coils mount to. It could also be caused by a bad crank sensor signal. The only way to rule this out is to test the crank sensor with an oscilloscope. For what it's worth it looks like the ICM is at fault roughly 80 percent of the time with this symptom. Good luck! Hope this is helpful!