Random stalling

[Bostinn]

My VY ecotec is randomly stalling every few days. It will struggle to keep up revs then die.

Some days it will start then die like it has a vacuum leak on the throttle body but no leaks are present.

Other days it will run perfect. This happens hot or cold.

Checked voltage
Swapped fuel pump relay
New crank angle sensor
New fuel fillter
New plugs
New leads
Different Dfi
Trans service
Cleaned Maf and throttle body
Checked earths

Cleaned and silicon sprayed every connection

On occasion it will just crank and nothing happens, battery health is low but has no trouble moving the starter at all.

Voltage regulator looks worn and will need replacing but I dont feel thats my problem as the battery cranks well after it dies.

Only once have a recived and alternator warning but I always get a battery light, due to the belt not moving fast enough from lack of power

Could the battery drop the a cell temporarily? But that still wouldn't explain a strong crank.

I used to be able to put it into neutral whilst rolling and it would start right up. Now it doesnt.

210,000km on the engine