AU2 75th Ghia 6cyl - this car just powers off and die as soon as I start to drive off
Sometimes when more gentle with the gas I might be able to just eventually make it slowly off without stalling but mostly it has to do this once each time I startup and start moving.

Sometimes also it stalls and then picks up and drive off - but it has to happen once in every trip.
When it stalls power is completely off for a second and I know this because the alarm starts going off - just like when I disconnect the battery.

I replaced the O2 sensor the other day - same or even worst so I put the original one back
I cleaned the ISV and throttle body - not much in there it was all clean - same
Car has always been serviced and all plugs and filters and oil and all are all ok

The other thing I noticed - the range im K's for the petrol has now jumped to a higher number - not sure if this is right or not

Could it be the cat or map sensor or anyone come across this before pls help me !!!
thanks in advance

Alternator ? Is it showing low voltage charging ?

Volt pretty high, however this started since I bought a second car which means - I dont drive the AU as much anymore I only use it to go to the station in the morning to go to work
But it cranks and starts everytime with no probs

This happens either hot or cold start
As soon as I start to drive off - it stalls and all lights and everythng cuts off then it tries to pickup again and sometimes it just then drive off normally and for the rest of the trip until next start.

Car is over 300k and been really good all serviced always and stuff - could it be the fuel pump? Or coil?