Fiatpunto alx.2002.. sometimes after ive driven to local car park.on returning ituern the key .s ounds fine. but but doesnnt start the motor..after 16 turns of the key ,it starts. it happends at random.. mechanic cant find any thing wrong.ive had a new battery . had it tuned.had it serviced.. most times it fine.. once mechanic had to pick it up when it wouldnt start at all..im at my wits end..can you help.!! ta.. v.bain