hi had my 16v for 2 weeks now and its been fine, i no its needs a service an the breathers cleaning out, but this morning i had to go out an my car fired up fine but when i had to fire it up again, it fired up then cut out, i then tried it again and it was fine, but i have just been outside to try it again and it fires up then shuts off after 2 seconds, an it keeps doing this

ANYONE GOT ANY IDEA WHATS WRONG COULD IT BE MY IMMOBILISER? CHEERS DAMO