Cutting out

So now I have a new problem, a bit like the one in this thread. 

http://pajerio.com/forum/low-iddling-when-stopped-pajero-io-1999#comment-18000

Took the car out this morning, it is -1C.  I wanted to see how it would perform first thing in the morning in a cold sart situation.  Guess I asked for what happened.

After it had done a mile or so it started to play up at junctions and anywhere that I had to stop.  Idle speed gradually got lower and with an auto it is not really possible to get away with a car that will not idle when stopped but I got it home. 

In N it is just about able to hold its own but in park it dies off rapidly.

I can keep it alive at idling speed by upping the revs with the throttle.

Am I right in thinking this is going to be to do with the air sensors behind the filter housing.