engine managment light?

my car's engine light is coming on all the time and goes off it has stalled 4 times and some times its hard to start agian. i was coming home from work this morning and when i was doing 5 thoasnds revs it was if it was at its limit cutting out and it does it in fifth gear when i do 80to90 mph any one any ideas its a vauxhall vectra sri 140 s reg