Sharan cuts out oil light flashing?

My VW sharan petrol 2ltr W-reg auto always works fine when cold but when warm intermittently it will cut out lose all revs oil light comes on and sometimes an alarm will sound. if i pump accelerator sometimes fixes problem sometimes not and then i have to wait a few minutes and start the engine again normally fixes problem but recently not restarting straight away? any help would be good thnx