2006 Camry Weird Engine Noise - No lights or codes

[weber846]

Good day to all, 

I am posting this because I am completely stumped and I have no idea where to look next. I have a 2006 Camry that I use to drive into the city everyday for work. It is about 30 miles in and 30 miles out of the city. I am hearing a very loud engine noise, from riding inside it sounds like a Fan boat is turning on and running inside the car. When it first started happening it was more constant and at low and high speeds. Being a 2006, I thought of the front bearings. I replaced those and the tie-rod ends. The issue seemed to go away for about two days. Now, when I am driving, am low speeds or just around town there is no noise. Once I am driving for a bit the noise comes in pretty loud. I was thinking the exhaust, but I crawled under the car and found no holes in the pipe all the way from the header back to after the muffler. I can understand engine noise getting louder as a car ages, but this is the Four Cylinder it should not sound like this. 

There is one engine code every once in a while it is the p0500 code for speed sensor, but this is not constant at all, it will come on maybe once a week. (I am just thinking a bad sensor somewhere.) However, the engine noise is constant at high speeds. The only other thing it is doing, it sound like it is choking itself out at stops. I come to a stop, and the RPMs dip but never stall out. 

I have thought of everything I can think of, I am tried injector cleaner, for a stuck valve. I looked inside at the throttle body, it is a little dirty but I cleaned it when I bought the car about five months ago. And without any lights, warnings or  any other noises, I can't pin point the issue. 

So, if anyone has this issue or know where to look next, I am open for thoughts. Please let me know. Thanks