Upon reading on your first post, you've changed the MAF ,OK, checked spark plug, OK, replace air filter ,OK, premium gasoline is OK and now A/C checked OK. The only thing remaining is the throttle body. Have those been cleaned? A possibility there's gunk/varnish on the butterfly linkage from moving freely. Spraying it with throttle body cleaner might do the trick.
Note: Never clean with your finger/s inside the throttle body when the throttle body is still attached to the car, when generated by a power source, the butterfly could cut your fingers off. Just take precautionary care.

 

Mine does the same. Feels like it's stumbling at idle but smooths out at higher rpm. It's most likely fouled injectors. These direct injection engines are known for that. I'm also running a few bottles of injector cleaner through it on the next three fill-ups.

 

Shop said throttle body looks clean, low miles and without anything notable

 

How many miles do you have on yours? I'm surprised that that the injectors get clogged up with such low miles sub 20k miles.

 

Let me know if you've had any luck, I did 4 fill ups with different brand injector cleaners and its still running the same. Going to try BG44K next

 

I've used 3 different brands and haven't seen any improvement yet. Let me know how the BG44K works.

 

Haven't used BG 44K Yet, I don't drive much so I'm a little worried about BG 44K sitting in my tanks for 2.5-3 weeks (usually how often I go through a tank) How many miles do you have on yours with this issue?

 

Well have you considered that this may be at least contributing to what you're describing?
These (and the fuel) aren't made to sit around. If you don't drive it as it's designed (by the laws of physics, not engineers) to be, and use the fuel & other fluids, you WILL have problems.
Your usage is probably a better application of an electric vehicle.

 

I don't think my car usage is in any way contributing to the current symptoms as I'm driving about 800 miles a month on a regular basis. I've been averaging 1000 miles a month for 2 months before the last month. Plus isn't fuel good for a 2-4 months? Perhaps its my driving style? I usually drive out at night where there's minimal traffic and my avg mpg right now shows 28mpg for 2500 mile trip average. I also throw the car into Dynamic mode for short bursts of spirited driving as well but never redlining.

 

Well yes then, I probably under-interpreted, under-estimated how long the fuel sits in your tank; so probably doesn't have much if anything to do with it.
But these cars are certainly made to be driven. I've heard several Jag mechanics and fellow owners say and have seen from our own use (myself more with my Range Rover).
They do seem to favor the long trips and spirited drives generally.

 

I use mine as a daily driver. It's just under 60k miles right now, and I go through a tank in 2 weeks or less. Mostly city driving, so my mileage isn't great (about 17 mpg). I don't get any misfiring or power loss, just that irregular idle vibration.

Crucial note: it happens whether the transmission is in neutral, drive, or park, so it doesn't seem to be a driveline problem.

 

I'm having the same symptoms no power loss either just the weird idle. How long has it been for you since the symptoms started? I haven't had the time to take it to a Jag dealer and both of my local mechanics told me its fine to drive and since mechanicals are fine

 

I bought it half a year ago with 50k and it's done it the whole time.

 

Hmm, just ordered BG 44K and going to use for my next fill up. hopefully it helps

 

My experience is , maybe it's a manifod gasket. Mine did the same thing, It went away when I changed all 6 gaskets. These rubber things do failed after years of heat.

 

Thanks for that insight! Do you remember how much was the cost of that job? it does make sense due to rubber wear with heat & time.

 

Does the vibration at idle lessen when warmed up. I have an iffy torque convertor on my car that does the same thing when fluid is cold. Took me forever and asking zf themselves to pinpoint it. Just a thought. No codes ever. Has to do with internals. Leaking internal seal and possibly stator going bad

 

My suggestion is ,leave the car in the machinist maybe overnight, redo the leak test in the cold morning . It will be much easier to pinpoint these seal problems. Gaskets are cheap on ebay, but the manifold has to taken off to chang them. So be sure before do it. good lucky.

 

Interesting question.. I wonder if the cost in China is the same as where ever you're at, unless of course you're in China too.
You may have to convert from Chinese yuan to your currency.

 

😄you right! can't answer the question What I can tell is labour cost almost the same as parts.