Hi, i am attempting to diagnose a dead misfire on two cylinders. I have a 99 regal n/a with a 3800 series II engine. While driving one day it began idling very rough and lost some power and was driven a few miles home that way and parked. I figured out that cylinders #2 and #5 have a dead misfire, which both share a coil so i figured that was the problem, but after replacing the entire 3 coil assembly with a known good unit there is no change. I am stumped and would some help finding which direction to go from here.