My car makes a dull knocking sound which kind of sounded like the piston slap from my previous car but to a much lesser degree. On cold start up, the car doesn't make the sound until after 15-20 seconds then it starts knocking. It's a quiet dull knock during idle and light throttle until full warmed up. When the car is fully warmed up, I don't hear it under throttle anymore but I can still hear it very quiet during idle. Any ideas where this sound is coming from? I hope it's not rod knock starting... oh and oil pressure seems to be good, cold start it'll go up to 6 and when warmed up its around 2 on the stock oil pressure gauge. I was using 5w40 before and I just switched to 0w50. The sound is still there.
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