Hi! This is my first post.
Back in December 2015, I got a used 13 JKUR. On the test drive, I noticed it "ran rough" at idle when stopped at lights. As a long-time Jeep enthusiast, it didn't bother me too much. I figured it's just been sitting on the lot and had stale gas or something. However, almost 15k miles later, the issue persists.
To elaborate, this is not an issue with engine operation. The 3.6 purrs like a kitten. I'm reasonably certain that this is a vibration isolation issue, like a motor mount and/or transmission mount isn't doing its job.
Furthermore, when I'm idling with the Jeep facing uphill, the shudder is more prominent, and when I'm idling with the Jeep facing downhill, it is vibration-free and as smooth as silk.
I had the dealer look at it, and they were absolutely useless. They said the mounts looked fine, then they cleaned the throttle body, and said, "Here. See if that helps," and sent me on my way.
Months later, I had my man take a look at it. He said he felt it too, acknowledged that I wasn't crazy, and agreed that it isn't an engine operation issue. Something is "out of balance," but he regretfully couldn't figure it out.
After some Googling, I read about a few other cases that sounded kind of similar to mine, and they claimed that a new tranny mount solved the problem. So aside from this post, that's my plan of attack - to just start throwing parts at it over time hoping it will go away.
You guys have any thoughts?