Hey Brickheads. Recently my 86 244DL (347,000miles) has developed a rattle when the throttle is released on the highway. The sound is quite metalic and not unlike resonating tin ductwork in an old building. At first I believed it was the air intake pre-heater hose that I had disconnected, but that was possibly contacting the exhaust manifold heat sheald and rattling. Well I yanked that whole mess out along with the airbox thermostat...no dice...all that did was give me a tiny bit more fuel economy...Any idea what could cause this issue? It is odd, as even the slightest crack of the throttle body stops the rattle....and it only occurs at speeds over 60mph....I really hope that this is not a warning of bottom end failure, but when i have heard that before it has been a more dead-thunk sort of sound, not this tinny resonating business. I recently installed a new starla cat-back system which resonates a lot at wide-open throttle, but i am not sure that this has anything to do with it...aside from the strange noise...she runs like a top...any ideas?