My 3.9 v8 wont start. a couple of weeks ago i noticed that when my rangey was running on gas it would missfire and splutter when under moderate to hard aceleration, once switched over to petrol ot was fine. over a couple of days this graduatly got worse untill it would tick over on gas and as soon as it went into gear (auto) would dye. On petrol was slightly better but couldnt drive it. I decided to remove leads plugs and cap to see what condition they were in as i have just bought the car and they were in a bad state. after deciding that they would need to be replaced in put it all back to gether to move it out of the way of the garage on petrol and it wouldnt start. i have checked the firing order time and time again and still no luck. I know all the ignition componants need replacing but it still should atleast tick over the really werent that bad. Now it will start and tick over at abot 150-200 rpm and if i put my foot to the floor it will gradually rise to 1000rpm and go no further. when at 1000rpm the V8 sounds fine with no missfire or splutter but then will dye if foot is taken of the gas. i dont wanna be spending money on new leads plugs etc etc if there is a major problem, im sure this ha nothing to do with them because as i said before it was ticking over fine. Can anyone help please?????