I have a SC300 too. It just started pinging about 45 days ago. I had the 15K maint. about 6K ago. I have not sent to dealer, no time. I am using high test(91) from Cheveron. I just did an oil change and cleaned the K&N filter. I have an AUTO. When running the RPM below 2100 + or - 200 I can hear the ping when lightly accelerating. If I gas it, the ping goes away after about 2100- 2400. After that my acceleration will not ping, light or pressured. I am lost. My ping is low RPM light acceleration.....