Obviously you guys are in a different country so the setup of the unit may be slighty different, but having spent the last 5 yrs on toyota in oz you should find if it has a 5k or 4y engine in it, it already has a vacuum operated idle up device on it.if you look under the bonnet it on the rear of the carburetor towards the radiator. Most trucks of any brand have used these for years, it nothing new. Id go with bighusky's response that it more than likely hasnt been tuned properly.