Sometimes idles rough then stalls

Holden rodeo 3.5v6 2005, sometimes idles roughly then stalls. When actually moving the vehicle would appear to run as if there is too much fuel going in to the cylinders and when you pull up at a set of traffic lights, it stalls. However, this doesn't hap

Vehicle has had oxygen sensor and idle stepper motor replaced. It has also been recalled by Holden for a software upgrade but still persists with the fault as stated above.

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