If you hook up to a scanner with mode 6 it will tell you how many misfires you have per cylinder after startup. That could help you determine if it’s a mechanical issue or just an NVH issue.

 

BG 44K works great. I've also had excellent results with Red Line SL-1. Different formulations may provide different results.

Vince

 

Just used BG44K in a 75% full tank. Within the first 100 miles of driving, the car felt noticeably smoother. The rough idle/stumble is still the same intensity at idle/park. Guess I'll find some time to bring it to the dealer for diagnosis

 

Did an oil change today and rough idle smoothed out about 30% give or take. Vibrations are still there but definitely less noticeable. Still had 1/4 tank with BG 44K in it when I filled up today so not sure if I'll see any more improvements with this tank of gas

 

Update, took the Jag to the local dealer and they said the car isn't misfiring, air fuel system are all rock solid. Most likely issue with one of the mounts but they couldn't find the faulty mount after initial inspecting. Car isn't showing any codes from their diagnostic system (aside for my broken front roof shade) They recommended if I could live with the vibrations just keep it as is and come in if it ever got worse or I could pay for them to do a thorough inspection to identify the culprit. Currently keeping it as is since its only noticeable when I'm stopped. Glad to hear that I'm not having any misfires or engine problems

 

If the engine mount really starts to lose fluid, you'll notice the "ribs" on the intake start to sag assymetrically. I.e. the side your mount is sagging on, looks pinched or pushed together.

The dealer kept telling me, it could be a variety of reasons, and truthfully it could be. But it was the motor mount, like I told him xD