2011 SE 2.5, "puttering" sound from behind the engine
 

I have a 2011 Camry SE 2.5 L4 with 145k miles. Never any concerns. Maintained by the book.

With Spring weather, driving with windows down for the first time, I hear an exhaust like "puttering" sound from the mid-front of the car.

I crawled under it today to look for exhaust leaks and find none. The sound seems to be coming from behind the engine up above where the exhaust manifold even begins.

Any thoughts or suggestions?

Above the exhaust manifold?

Yes, it seems to be up above the manifold somewhere... Admitted, my hearing is horrible, but
I feel no exhaust leak at the manifold.

Also, I note that when the engine is under a load... in gear, it is more noticeable.

Use a section of rubber hose as a stethoscope to narrow down the location of the noise.

The engine intake manifold has a device that alters its functional intake length by using valving. This valving can make noise. Check for noise around the intake manifold.

Thanks for the advice.

Any luck finding it?