3 potting :S

[The_STIG]

i have a phase 2 vtr and recently its started to 3 pot every now and then but i have noticed that if im just cruising and maintaing my speed thats when it 3 pots if i put my foot down it fights thru and goes like normal im thinking plugs and leads or head gasket but does any1 have any ideas as to what else this could be just incase its not any of the above:y:

[-Jason-]

Does sound like a HT lead problem or sparks head gasket check oil etc see if gloopy other than that not sure try the cheapest first and process of illimination.