Please help, my gf's 20v black top engine got pinging when pick up. almost everytime i press the throttle more than 50% it starts to ping. I've tried adjusting the timing and it got much better but after i drive/rev for 6-7 times it starts to ping again. Already changed black oil and don't know what should i do with it, it's a bit hard to diagnose, pls give me your opinions if u've experienced this problem before, thank you very much!

... I'm looking for the standard size filter not the mushroom filter...