my 4cyl Toyota was doing the same, I changed the spark plugs and wires and it runs like new :)
A loose or worn belt. Also check the power steering fluid.
Bad CV joint, loose rim, Loose caliper
loose or worn belt
lifters are beginning to go. timing chain (if vehicle is equiped) may be coming loose. and or exhaust pieces are loose.
84 dB at that point
Could be your brakes. If you have drum brakes not disk brakes that sound will happen when your shoes are worn down to the rivets. Some of the hardware such as springs, may have came off as well, which will make the loose metal sound.
from a distance away why does a jet sound loader than a lawn mower
Loudness: Sound power is the cause, but sound pressure makes the effect. Scroll down to related links and look at "Sound pressure and sound power - Effect and cause".
from a distance away why does a jet sound loader than a lawn mower
Check to see if your trunk is open or if the clasp that holds it closed is loose.
The sound of a jet engine vibrates more than the sound of a lawn mower.
Most common cause would be a loose brake caliper mounting bolts.