I've put almost 31k on my 2008 IS-F and recently noticed that intoxicating noise when downshifting is gone. When using Sport mode and downshifting the Revs match and you get some intake/engine noise. That sound appears to be gone on my car recently. All maintenance has been done to the book by Lexus, minor stuff like filters has been done on time by myself.

Any thoughts? I'm sure the recent recall for the gas pedal modification wasn't to blame.

The car is scheduled for service next Monday and this is on the list.

 

Do you get the increased "roar" when accelerating hard through 4K RPM? Check the secondary air intake "flapper"; maybe it is stuck and not opening.

 

I do get that. Downshifts are almost silent unless I put my foot into it.

 

Strange. I noticed the same thing for a week, but now it is back. Perhaps I was not being as aggressive before?

 

the sexy downshift noise u speak of happens when above 3600 rpm

 

I think i'ts getting driven aggressively. Current mpg is 14-18mpg. :-)
Correct above 3600 when the 2nd intake is opened. I'll make sure the dealer checks it out. Might be fun to take a tech for a drive and explain this one.

 

Last night I went up and down the highway to try it. I only got the sound to appear if I downshift and the Revs climb to 5k+. I know when the car was younger it would do it at much lower revs.

 

Clogged cat maybe?