Ok Guys, yet another question for my 2000 2.5

since my last venture under the hood for plugs and wires, my 2.5 has developed a strange issue

when I crank her up or shut her down, it feels rough. Almost like the engine is shuddering under the hood. Now, and only at idle, there is a new, quite noticable vibration. RPMs are constant so I dont think its a fuel injector issue or ignition issue. And if I take the engine above idle, even just a few 100 rpm, it smooths out perfectly.

my only thought is my engine mounts could be shot


now mind you I dropped a plug under the engine during the first sparkplug replacement, perhaps the engine is rocking against the plug under there and is throwing off the dynamics of the system

y'all have any ideas on this matter