Rough idle can be a sign of a failed PCV valve on the back of the inlet manifold. If the hoses where bad enough to warrant changing then it a good chance the valve has failed or is failing. There is a vacuum test you could try on the rocker cover, but this needs the right equipment that the average Mechanic won't have. A lot of people in the know consider this valve to be a service item as its very important in the correct running of the car.
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