ef cranks but wont start,at first test there was spark on number 1 plug, but i checked some other plugs and there wasnt any spark at all, now and then you would get some spark then just stops , ive tried on gas and petrol, neither start, fuel pump is humming away, i tried to start it again this afternoon and it backfired straight away, its been funny sometimes it starts sometimes it wont start, leave it a bit then it starts, has had a problem backfiring on gas when starting
could it be the coil pack or crank angle sensor? any ideas thanks

most likey coil if your getting spark on some and not others

this mite sound bit strange , but have u had ur hand down by ur coilpack at all, cause i was mucking around with my hands down an around coil pack and knocked off the plug and would not start for hrs untill i found out id bumped off the plug so have a look at least