ford galaxy 2.3 struggling to start an cuts out?

my galaxy is struggling to start when started sometimes cuts out while driving but some days fine battery been charged overnight but still didnt want to start but drove fine.its intermitant an my dad has checked battery with a multi meter an it was reading low but could it be that the fuel cut off reset switch has been knocked as i have had a bag by it the last few days an this is when it started.or could it be something else ?

craig
June 2009