Engine niose

The engine has been replaced and now has about 90k miles on it. When the car is at idal there is a noise that it makes. kind of sounds like wattle, wattle, wattle over and over again. When the RPM increase it goes away.

This was going on prior the engine replacement. The shop can not diagnose the problem. Any ideas?

Okay–let’s see if I understand your question.

The “old” engine made a “wattle, wattle, wattle” noise.
The “new” engine, after an unknown number of miles, makes the same noise.
Is that correct?

I think that, unless there is some kind of mass defect in Mazda engines, the presence of the same noise with two different engines leads to the probability that the noise is coming from an area of the vehicle other than the engine. One possibility is a loose heat shield on the exhaust system.

My biggest problem is figuring out exactly what this noise actually sounds like.
I cannot identify anything that coincides with “wattle”, other than a part of a turkey’s anatomy.
Can you post a sound file of the noise?