Hello, I own a 95 Accord. Bought it recently from a buddy of mine who had never had this problem or noise when he owned it (I rode personally in the car multiple times and had never heard it.) He had left it sitting for around 2-3 months before I bought it from him and about another month or so before I actually got it from him.

Anyways, to the problem. The problem is not only when I decelerate but that is when it is the most noticeable, the sound does sometimes occur when the car shifts between 3rd gear and 4th (A/T). It is a quite loud grinding and/or knocking noise coming from the engine of the car, sounds like the car has no oil but I assure you it does. I'm also not sure if this is the same problem or just a different problem but when braking at low speeds it is sort of grindy. the car will also make this sound for a quick second if I put it in reverse kind of like a popping type grinding sound. I drive on the freeway around 2 miles to work and getting off on the exit is when it is the loudest, when I let off of the throttle it makes a very loud grinding sound until it gets around to a low RPM.

I apologize if this is not descriptive enough for the problem I am having, I'm not car savvy enough or awake enough to think of the words to describe it better. I will try to take a video later tonight of the sounds it makes.

 

You need a mechanic stethescope and narrow it down.

 

Its probably a failing CV axle. Is it knocking only when you decelerate?

 

Yo I had to take my gas tank down and replace it, as a result my exhaust as well, after the job complete I also had a horrendous rattle on deaccel, turned out at first elbow I had a loose mount bolt + the aluminum heat shrouds are all loose as hell.