99 Expedition engine is "shuddering"

[exdeath]

#4 is the rear passenger cylinder, Ford engines are labeled:

rear
4 8
3 7
2 6
1 5
front

Make sure the coil pack cover seal is clean and the rubber grommet where the signal wires enter is seated right. Lining up those grommets can be a pain, so most people just slap the cover on and bolt it down smashing the grommet or whatever, allowing moisture into the coil packs.

grommet |- =| under side of coil cover

 

[thomsbrain]

I did some intense googling and found that there is a service bulletin with this exact problem!

Apparently the problem is that it's a Ford. The recommended fix is at your local GMC dealer.