Each time I start my cold car in morning and while in Dive, I hear a clicking or ping nois. If I take my foot off accelerator the noise stops. This lasts for about 15 minutes and the noise is gone. Toyota told me the ticking noise is metal in the engine expanding.
Recommeded Premium Gas for cusstomer but will not have to change gas type.
Also told me that retarding timing will not reduce gas mileage.