sounds like the rubber damper is worn on the harmonic balancer. if this is the case you will have to replace the harmonic balancer.
Clanking, rattling, pounding??
could be a bad motor mount.mine was bad and I got a lot of vibrating / rattling sounds.
It may be the heat shields on the exhaust system vibrating.
tie rod.... your tie rod rubber wore out...needs anew rubber or new tie rod
Could be a, broken flywheel (flex plate), blown transmission or blown differential.
My Hyundai Elantra 2008 GLS with 13,800 miles on it had a vibrating rattle especially when idling but also while driving although not always. I bought the car used. After four months of going crazy with the sound we found that it was coming from where the back seat joins the frame. It is not tightly joined there nor is it cushioned. We stuffed some thin cardboard around it to tighten it. That keeps it from vibrating and rattling.
the muffler rattling? the muffler rattling? the muffler rattling?
What causes a hard rattling knocking sound under the hood when you start your 98 ford windstar? Lack of oil, lack of oil pressure, badly worn camshaft or crankshaft or a combination of all the above.
Dynamat usually does the trick, also try removing the trunk liner and seeing if anything is vibrating noticeably inside it. http://www.dynamat.com/
Possibly: A faulty shock - incorrect installation - a mounting bolt not tightened sufficiently - something touching the shock/strut and vibrating against it. Take it back and complain.
Front or Rear wheel bearings may need changing, can be a tire out of balance, bent wheel, motor count broken, just to name a few things.
its in the top end ..its the wrist pin that holds the piston to the crankshaft..but its fine just run the hell outta it ,it wont hurt nouthing cus its a Honda