Irratic Idle & Stalling

[pasherp]

I own a 2.0 litre auto t-spirit avensis on a 04 plate,done 35000 miles and full service history.

The problem is when the engine is warming up revs are at 600 rpm and engine is irratic until it gets up to normal running temp then you can suddenly see the revs pick up on the rev counter and hear the engine pick up.The engine sometimes stalls at junctions when temp is not up to normal running temp.Its had new fuel pump on and new fuel lines and regulary use injector cleaner.

Anyone got any ideas what to check and how and have you had this fault?