I did the oil change today using Mobil 1 0W40.
Did the Italian Tune up yesterday and the car is running perfectly. Very quiet at idle and not a single ping or anything else. Just the light purr of the engine.
Thanks to everyone for the advice and could not be happier!
I followed your posts as well and learned about the Italian tune up, I already performed it in the Celica GT-S but my GT which after sitting for a week and 4 cold start ups to move it up & down the driveway. Each time the car shook vigorously and had a rough idle.
Performed an Italian tune, and the cold start up this morning was perfect and back to normal. Glad it worked out for the both of us.