running lumpy zafira 1.8 2003?

my sister has a 03 1.8 zafira and its running really bad to say the least butit has been to the garage and they sais it is a cylinder gone and it would cost her a lot more then a 1000 to sort out but i dont think it is so im trying to find out any more answers it has had new plugs new oil new air filter and rear petrol filter changed when started it idles at bout 600 but with pumping pedal fast it revs bit faster i have cleaned throttle body egr is blanked off she cant afford to much so could anyone give me any advice that is worth tinkering with to see if that helps cheers john