I plan on doing a valve check but doing the engine mounts, at this point, is actually the cheapest, if not the easiest thing to do. I want to do that first mainly because I know they're shot and at least contributing to the shaking. If the shake is a valve thing, I figure it's really important to at least get it more supported so the shaking doesn't destroy the drivetrain while I save up for the kit to do the valves.

I figure it's not the rack damper because it doesn't have sort of a floating idle, it just shakes and holds idle at the exact speed.

My gut tells me it's either the injectors or the mounts or both. It could be that at idle the injectors are spitting fuel out poorly because of the lower pressure and the monte are so shot that it lets it shake way more than it should.