ABNORMAL/OSCILLATING SOUND: like a marble being shaken inside glass container

[Ventimocha]

I'm a newbie so please bear with me...

I love my '87 Wagon (4 cyl manual transmission). A few days ago I ran the car really hard (excessive downshifting-braking-acceleration... you name it) for about 15-20 minutes. After I dropped my dad off at work (on-time :o)) I immediately resumed normal driving habits... trying to take it easy, if anything.

On my way home I put a couple of gallons of gas in the tank and didn't notice anything out of the ordinary, except the muffler(being in dire need of replacement) sounded a litle louder than the low roar it normally operates at.

I was sitting at a stoplight, 2 blocks from my h ouse when I heard the knocking/rattling/clanging (for lack of better words) sound(s) coming from under the hood. The light turned green and I drove the 2 blocks to my house with no performanmce problems and the sound seemed to go away when the car was in gear.

BUT...I'm worried that driving it will make the problem (whatever it is) worse...so I haven't driven it since.

Initial diagnosis by my"car-savvy" friends...punched a rod through the engine block or oil pan....
Revised diagnosis after having heard the sound in person..."don't know what it is" and "never heard anyting like that before" have been the popular.

The sound: Like a small marble banging against the walls of a glass container. It oscillates...sounds like it's moving around from the top of the engine compartment to the bottom...BUT...sometimes sounds like it's coming from somewhere near the belts (passenger side). Varies in volume as well as intensity. It is loud then quiet, then loud, then quiet....intense then softer, then intense etc. Took off valve cover(?) and everything looked fine at first glance.

Don't know what to do... friends say it could definitely be someting other than rod... but can't say what...

Please Help!!!

I have put a lot of work into this, my first Toyota. I don't want to have to let it go.
Working w/ VERY limited budget... but quick learner and determined!

Please share your thoughts/ideas of possible problem(s)/solution(s)!

[Doctor J]

Could be motor mount/exhaust system

[Mike Gerber]

Are you familiar with what pinging sounds like? Is the noise worse when going up hills with a warm engine? It could simply be pinging caused by low octane fuel (you did mention "On my way home I put a couple of gallons of gas in the tank"). Carbon in the engine, or problems with the EGR system, along with overadvanced ignition timing can also cause pinging.

Mike

[scribby]

Sounds like pinging, also I would check your oil pressure.

[Kep]

Sometimes when a catalytic converter wears out the contents will make a rattling sound. Maybe you could tap it with a hammer and listen to see if the stuff inside is loose.

The CVC joints make a wierd sort of rattling noise when they start to wear out. Typically you will notice it a lot more when you are turning one way or the other. If one or more of your CVC boots are torn this would be very likely.

If the heat shield on the front of the engine exhaust gets loose it has a rattling noise.

Don't know if any of this is of help or not.

Kep