Ok so the background is this...I bought a slightly used 2008 IS350 (6K miles). I'm sure that the previous owner used 87 octane fuel. When I first got it, I'd sit in the garage, turn on the car, put it in drive and listen to the engine from inside the cabin (radio off, windows up). I noticed a slight knocking noise from the engine...very faint.

I've since been using only Chevron Techron 91 Octane and even put a nice bottle of chevron techron concentrate in there to clean the previous owner's bad habits. I've noticed the knocking became more faint but it's still there...very very very faint. Now this could all be in my head, but when you guys sit in your car at a red light or stopped....are your engines completely quiet? Is there any kind of a faint engine knocking noise at all (again very very faint). I bring all of this up because I was sitting in my buddy's S4 and his engine is loud...and it makes a constant growl but not a definiteive "knocking noise" of any kind. I guess I'm just worried about what the previous owner may or may not have done to the engine.

I'd appreciate any feedback....if this continues to bother me, maybe I'll go to the dealership and listen to the engines of anothe lexus.

Also, another side question - is it better to put the car (automatic transmission) in neutral at long stops/red lights?

Thanks Guys.

 

They all tick, I believe its the injectors?

Edit: This should help with your questions.

https://www.clublexus.com/forums/is-...d-threads.html

 

Mine ticks ever so slightly, as well as the ES350 I've been driving lately. Sounds just like the ticking in my '08 Scion. I, too, believe it is the injectors.

 

congrats on the car, and maybe check out the link above may help to explain a bit.

 

Yes...that is the exact adjective to describe what I'm hearing...an ever so slight "ticking". Ok this is good to know...Thanks for the feedback guys.

 

definitely the injectors