took my rx300 2000 to the dealer and they checked it out and no codes they did a little adjustment for the timing but still pings/rattles.. up hill loads at any speed.. then I took it to the auto part store to have them do the code readings and still PASS no codes.. the Lexus has around 109k miles on it... ok now we just bought the car like 4 months ago.. and we have been putting regular unleaded in it for about 2-3 tanks worth.. then we found out it takes premium so we been using Chevron premium and still pings. other than that car runs great.. The dealer dont know what to say. auto part store said try replacing the feul filter,,, HELP!

 

A full tank of gas and 18 FL. OZ of MARVEL MYSTERY OIL in your fuel tank twice in a row right before you'll make a long distance trip ( 30-ml )will take care of the pings like it did for my 2000 RX300.