high idle and missing?

[markostarletturbo]

 engine missing and high idle

Recently the GT has been idling at 1200-1400 rpm and has a miss when first accelerating seems worse when warm/hot also on a couple of occasions I've put the boot down and it's missed like f*ck 1of times I was on motorway in 5th put boot down and again missed like f*ck any ideas? I've changed dizzy cap and rotar arm leads are not that old and put new plugs in denso irradiums around a month ago Cheers Mark