Just had the same problem with mine. Misfire in cylindar 4 due to bent electrode. Took it in and the dealear said it was due to a missing screw on the intake mani. I expressed my concern that since they didn't find the screw they needed to remove the head and inspect the cylinder for damage. Refused to do the inspection. Just installed the new intake manifold and guess what? No compression. Now they're pulling the head to inspect for a possible cause.
Gotta love it...
Gotta love it...