Engine ticking sound at idle, happens after engine is warm

[Chen Zhao]

Hey everyone, I am trying to find a possible solution to this and need your help!

 

2004 Boxster S, 125k miles.

Driven DT 5W-40 oil.

No other issues and drives great.

 

BUT, whenever the car is warmed up and I stop at a traffic light or something, at idle, there is this rhythmatic ticking noise, and especially loud when there is a car beside me (I guess sound wave bouncing off of them or something). This noise, however, goes away completely with the slightest rev increase, say 800 (idle) to 900 or 1000. But returns again after I let off the accelerator pedal.

 

https://youtu.be/DyiW3X4JVJ4?si=YGRwD6nPx-vAXeb2

 

No misfire or anything, no ticking noise when car is cold and idling.

 

I've seen posts suggesting this is lifter and using Liqui Moly Hydraulic Lifter Additive could help?

 

Oh, and I have replaced all 6 spark plugs but that didn't resolve this.

 

I would really appreciate any help! I might try the lifter additive anyways if there's no harmful side effects.

 

Thank you.