What a fun day!

We've been chasing down an odd vibration in the truck that kicks in at about 55. Wife thinks it's a wheel bearing, but I'm not quite there 100%. We did change out the LF wheel bearing and CV axle. (Rockauto for the win!) And for once the wheel bearing didn't need to be taken to a shop and have the holy Moses beaten out of it.

So I decided it was time to change out the plugs and figured we'd also change the coil 'boots' at the same time. This is where things went pear shaped. The last owner must have figured he needed to use super strength as the small 10mm nuts are fused in place. Between the light coating of rust on a few of the retaining bolts- And some are pretty crusty. I did manage to work 2 free before hitting the brakes on this part of the project. Now when I say "work free"? It was the entire shoulder bolt/stud that started to unscrew.

Would this be the correct part? Trying to think ahead in case we have these break. Currently I put the 2 we removed back in and snugged them down with a liberal coating of PB blaster.

Double Ended Stud, Mounting - Mopar (6509136AA)

Now that's out of the way: Do these mounting 'studs' also retain the plastic intake to the lower intake? Reason I'm asking: If I start removing these 'studs' sense the retaining 'nut' seems to be frozen in place. Would this also mean I need to remove the plastic intake and replace the intake manifold gaskets? Just looking for advice and options. This ol' girl has a full bank miss fire at odd times. So we're trying to do the simple things first. Sense the last owner claims he replaced the plugs, If he ran into the same issues I did? I'm wondering if he broke the seal to the intake manifold and that's causing potential vacuum leaks. I can see replacing the coil boots and the plugs--and having to fully remove the entire stud, as the nut is likely not coming free

 

Minor update:

Drive line vibration is gone. Seems that oddball (and very miss-directing) noise was either that wheel bearing or the CV shaft.

So that leaves the bolts that are still in question. I'll ask this one get closed out, as it might be better to combine another topic with the bolt one.

S-