My 1993 truck makes a clattering noise when I let off the gas between 2500 and 2200 RPM. It has 132K miles on it. It sounds like the old V8s with loud mufflers. I don’t think it is coming from the exhaust. It sounds like it is in the engine compartment.
If you have a blown gasket in the engine’s exhaust sytem, you’ll get a loud noise from under the hood. Have a good mufffler shop check it out. It could be an exhaust manifold gasket ar a cracked exhaust mainfold.