Couple of Car problems help?

[AHADTHEONE]

whenever i start the the car the first 3-4 times the engine turns off straight away. this happens at random times whether hot or cold. whats causing this?

2nd prob is after i park the car i hear metallic knocking/pinging noises coming from the car. why is that?

thanks,

ps its a 2006 peugeot 206 1.4 verve