Renault 19 engine cutting out during in hot weather

[arthurjenner]

I live in the state of New South Wales in Australia.
own a 1994 Renault 19 automatic which I bought new. Last year(February 2003) during a very hot summer spell (circa 38 degC) I was driving home to Blackheath(altitude 1065 metres) in the Blue Mountains from Penrith (altitude 40 metres aprox). I reached Blaxland(altitude 250 metres approx.) when the engine spluttered and died). I assumed fuel vapourisation. I waited about half an hour and managed to drive another 10 kilometres or so when the same thing happened. This happened continually all the way home . All through the remanider of the year the car ran perfectly until the summer began. This time the problem started early in the summer and now occurs regularly. I thought, as I said, it may br vapourisation. It usually happens when the engine has reached normal operating temperation. Once it happens, it continues to happen until the engine cools right down. I have suspected faulty thermostat and changed it with no improvement. I suspected blocked fuel filter. Changed it. No improvement. I supected Poor fuel tank ventilation so ran with fuel cap open. No improvement. Mechanic suggests heat related ignition problem. Doesn't sound lokely to me. Any sugestions?