i changed my oil today after work today with the first dose of auto-rx.i went about 800 miles with the oil and napa gold 1516 filter.the oil did not look dirty at all,just a little purple in color.BUT the oil filter was DIRTY and full of dirt and sluge.(i took it apart and checked it out)looks like it worked.the last time i used mobil drive clean 10w-30,this time i will use penz 10w-30 with a toyota oil filter.i have to be very careful,this truck is how i eat and pay my bills.but so far it looks like it worked so far.i will give a nother update soon.buy the way this forum is the BEST,great info and great people.thanks to all