Fellas, I am officially depressed.
My 4.4 has an intermittent fault and nobody can tell me what it is because there are not faults on the OBD.
The fault happens sometimes when you start the engine. Suddenly the revolutions go up and down (from 400 to 900 approx) and there is a sucking noise coming from the air filter number 1 and at the same time the main valve from the main manifold is opening and closing in time with the sucking noise.

I made a video for you today, you can hear the sucking noise and the click coming from the valve opening and closing.
This problem happens as well sometimes when you are driving, and sometime the engine just shut down completely (it's scary as a f....).

When the problem happens you just stop the car, start it again, if it keeps happening, stop the engine again, wait 10 seconds, start it, if it keeps failing, stop... so you do this 4 or 5 times and the car just come back to normal. Normal driving, and everything is OK again.
My wife is scared of this car, she doesn't want to drive it anymore. I have spent more than £2000 on different garages and they can not solve it because they can not make it fail and the OBD doesn't send any code about it.

here is video with the sounds
https://www.youtube.com/shorts/89MZqXm1d9M

I hope someone here can help me because I really love this car but this is really depressing, fellas, I don't know what to do.

Thank you very much for reading. Any help will be very welcome.
Hugs to everyone, and thank you again!

In the video, are you switching-off before restarting each time or is it stopping by itself? If it stops by itself then the engine revs need to be monitored by a diagnostic tool while it's idling to see if the revs faulter or stop completely. A failing crankshaft position sensor causes this behaviour and no diagnostic code is stored. Garages should have checked for this already but perhaps not.

In the video the engine is not switching off. The engine is on all the time!

It sounded to me as though it was restarted several times.

Pull off the connector to the intake just infront of the throttle and check the throttle plate is not loose as the control mechanism can sometimes break due to carbon build-up from the EGR system. 2012 TDV8 Vogue (L322)

@Yorch1; there seems to be three repeats of the same issue in the recording, correct ? It might be clearer to show a single instance. TDV8 4.4 2012

The engine is on all the time. The sound is the engine trying to get air

It appears that the video is on permanent repeat. I stopped it after it started replaying the same video for the 6th time. Hence the restarting isn't indicative of the issue.

For the sucking noise I add my vote for the EGR throttle closing, either because its loose or because the gears are stripped.

I agree with both GraemeS and Jaygee as to possibilities.

Not had the crank position sensor fail yet. The throttle unit on mine had a gear drive failure and caused similar hunting in revs to this. Mine went into restricted performance but did not stop. I removed the tb to check and found the butterfly loose. When I got the new one fitted I opened up the gear drive on the old and found gears stripped. Cause almost certainly crud build up as JG says. Cheers
Richard

(there are no such things as an ordinary FullFat, an ordinary cat or too many tools)
2011 TDV8 Vogue Santorini Black
Gap IIDBT

GraemeS, the EGR was blanked one year ago and the car was remapped.
Yes, the video starts again when its finished, I don't know why!

A how to from the WIKI here shows the TB removl and precautions.

https://www.fullfatrr.com/forum/topic48780.html Cheers
Richard

(there are no such things as an ordinary FullFat, an ordinary cat or too many tools)
2011 TDV8 Vogue Santorini Black
Gap IIDBT

Yorch1 wrote:

and at the same time the main valve from the main manifold is opening and closing in time with the sucking noise.

Yorch1 wrote:

GraemeS, the EGR was blanked one year ago and the car was remapped.
Yes, the video starts again when its finished, I don't know why!

2 or 3 months

GraemeS wrote:

Yorch1 wrote:

and at the same time the main valve from the main manifold is opening and closing in time with the sucking noise.

If the main valve that you refer to is the EGR throttle butterfly then that's another reason to check the butterfly for looseness.