Intermittent stalling on a 2.4 TD Auto

[PapaFade]

Hi all,
Been away for a while and have been trying to catch up a bit with everything at home. Been meaning to post about this intermittent stalling problem I've been having the past month or so.

Doesn't appear to be much of a pattern. Starting ok and idles fine as it warms up. But then periodically it enters a period of stalling at low RPM, particularly when approaching junctions. This was most entertaining when in stop/go traffic on the M3/M25 this weekend, the stalling continuing for over 2 hrs. On this occasion I was having to drive 2 footed, one on the accelerator, keeping the rpm up, the other on the brake, to stop the truck whizzing off whilst in drive, the AT oil temp light came on. Sat on the hard shoulder for 10 mins with bonnet up as instructed in the user manual. After this, the problem was gone and didn't happen again until today.

Is this a known issue? Has anyone had a similar (or this) problem before?

[BUSHWHACKER]

Check the level and condition of the transmission fluid. It's best to check it after a short drive when it's warmed up. Park up apply handbrake and leave the engine ticking over, cycle through all the gears, i.e. from P down to L and back to P. With the engine still running, check the fluid level on the orange dipstick, pull it out and give it a wipe then slowly insert it back all the way. Pull it back out and look at the level, it should be halfway in the hot zone.
It should also be red colour not brown. Top up or replace as necessary.

What does the engine idle at when warm? should be around 750 rpm.
Is the engine check light coming on?
May be just a case of adjusting the idle speed or there's an intermittant fault with the throttle position sensor.

[PapaFade]

Thanks for the reply BushWhacker.
AT oil is red and in good quantity.
I need to get a gauge on the idle RPM as the one in the car shows it at zero
No engine check light on (no warning lights have shown up when this occurs thus far).

[PapaFade]

Been working on a diagnosis. I've tried to replicate the fault and it is happening fairly consistently when the truck is driven without a 5-10 min warm-up period first, but AFTER it has warmed up driving a few miles down the road.

[BUSHWHACKER]

Probably the EFI coolant sensor is faulty then, causing too little or too much fuel.