this sounds a little like the problem my dad was havin with his 3door when he was driving it and then slowly built the revs up it would rev upto about 6 and a half but if he were to just boot it it would go into a mad miss fire an start banging so he tryed changing different things and it never solved it so he eventually swapped the engine bay loom and it help a little bit but still payed up around the 6 6 and a half rev range so he change the coil and main coil lead and its been working fine ever since just needs a tune up now.. hope this helps mate