Ron68

I just got a 2014 Lexus IS 350 AWD in September. My first Lexus. The dealer experience was very poor - Sales Assistant was useless and basically did not give a ******. That was surprising and very disappointing but they were the only one getting the car / color that I wanted so I put up with it. Would never buy a car from them again.

Anyway - it's a very nice car - the seats are a work of art and so comfortable and I love the steering which is really precise and has great "feel". Engine is good and has plenty of power for my needs.

I do have one engine problem and I wondered if anyone else has had this problem? When I press the accelerator when I am doing exactly 45mph I get this loud and very irritating whistling sound. It only happens at that speed - I don't get it when accelerating at a lower or higher speed. Took it to local Lexus dealer and the engineer there heard it. He drove another IS 350 that they had on their lot and he heard the same sound on that car at 45mph. So he has now escalated this to Lexus (I guess to Japan?). Has anyone else with this model noticed this? Any ideas what might be causing this?

Bass Mech

i heard something similar in my corvette, i am pretty convinced it was the throttle plate, when opened partially it causes a whistle sound. i think the air speed has to be just right through the intake. it may happen at other speeds but difficult to catch because there may be too much road noise or the engine speed may drown out the sound. my vette did it in 3rd gear and i just happened to hear it that time. like you i was able to replicate it only at a certain speed, certain gear and with just the right amount of throttle. seemed like after the speed increased enough, or the throttle opened far enough the sound went away.
does that sound like a similar scenario to you?

KumaF

I haven't got my IS 350 yet, but the he engine on my BMW has a sad sound at 2500 to 3000 rpm at hwy speeds. I guess it's normal especially for NA engines, since all the cars I have driven had some spots in the rev range where it doesn't sound very smooth.