Not sure about this, but if you recently bought the car, have you cleaned your throttle body? how about cleaning the maf?

Has anyone messed with your throttle cable? even thought the gs is drive by wire you can set the cable as high as you want (or low) and after a few mins on startup the car will automatically adjust itself.

I would check those two things I mentioned, maybe even replacing the maf (find a low mileage use one) and report back.

 

I have cleaned the MAF and throttle body. Even changed out the gasket when I cleaned the throttle body.

Not sure if the throttle cable has been messed with it.

 

With engine rpms at 2000 and vacuum gauge is still a steady 22" of Hg, I can approve that your engine is OK.

What kind of oil are you using? Also, add a bottle of Chevron Fuel System cleaner. Maybe that noise is from the injectors.

 

at least I can put my paranoia to rest...

Not sure of the oil used. Car is maintained at the local Lexus dealership for the time as it's under warranty. Have tried techtron a while back, but didn't notice a difference.

 

If you are using Dino oil, I suggest running fully synthetic oil. It will be smoother. Try it.

 

Sounds like an exhaust leak to me

 

He did mention he had an exhaust leak fixed by the dealer.

 

I asked the dealership and they use dino oil. Shouldn't be too surprised by that... I'll switch to full synthetic starting with my next oil change. Been thinking about doing a seafoam treatment. Worth a shot?

 

Try it and report back. There is a DIY on how to seafoam if you search

 

Been a year since I last posted in this thread, but just to update I switched to synthetic. Changed my oil (mobil 1) back in January. Noise is the same. I'm still continuing my hunt for that. I may just go to an independent mechanic, since I'm tired of dealing with the dealer.


In other news though my coolant temp has been nudging higher and higher. When I first got the car it was dead center on the second line. After the timing belt and pump (2 years ago) was changed it nudge slightly higher, needle still on the second line, but a hair higher. It eventually worked it's way up above the second line. I figure lets change the coolant and thermostat. Now my needle fluctuates at idle the temp is above the center line like before the change However on the highway it comes back down like , almost right on the second line. I'm hoping this is just because it's a new thermostat and not some other issue.

I am wondering if the problems all stem from when the timing belt and water pump was changed.

 

Must be the timing belt water pump. At least by reading your string