required to stop every 30 mins

[vwkiwi]

Sorted! Yeh.

The problem is with the thermostatically controlled flap in the air filter entry. By replacing the flexible aluminium ducting between the manifold and the air filter (£2) and by inserting a screw (free) to keep the flap closed, ie only taking air from around the manifold, the engine no longer cuts out after 30 mins or so.

Problem is due to the thermostat is probably buggered and opening the flap, hence the carburettor is icing up (and hence the 2-3 mins before driving off again). But given that the flap is not required to be only drawing cold air until air temp gets above 20C (not likely in scotland in winter), it does not matter that the flap is screwed shut.

The thermostat works off a temperature sensor inside the air filter housing so it is also possible that this could be not working.