The engine idles at 3-4000rpm yet drives normally. Disconnecting the vaccum pipe to the the MAP stops the continuous high idle but gets the engine hunting high and low, is this a simple reaction to the loss of the MAP in the system and showing a duff MAP sensor???
Thankyou - might be futile now as I just ran the engine for an hour with steel seal as water was seeping into a cylinder - in the last 5mins of running the engine purred like a dream and then chucked out a cup full of COLD water from god knows where. So now waiting til engine has cooled to see if the Steel Seal is as good as they say it is!