Thanks for the reply Ido,I have the vacuum pipe issue sorted but it did not change anything I don' have a nostart issue,just a persistent misfire when warmed up and under load if I'm very light with the foot I can get all the way up to 2000rpmin top gear as long as I don't come to a hill.I fitted new plugs when I put the engine back in and yesterday I fitted new HT leads,as to my knowledge they had never been renewed.It's a bit mystifying as the engine was running like a champ up until I pulled it to fix some oil leaks.She is definitely running on all four so I'm inclined toward a fuel delivery problem of some kind.Is it at all possible that If I had one tooth error on the timing belt it would have that effect? As I said earlier it's fine until it gets up to normal running temp.Sorry to be longwinded but I'm banging my head on the wall here.