I have a 94 accord, ever since I got it , there was a small rattle that happens when i press the gas .

recently the amount of rattleing sound got worse and its now accompanied with a very bad vibration sound.

I checked the tires and had them balanced and rotated but it didnt fix anything.

The rattling occurs with the engine revs ,I checked the exhaust and found that it looks like its coming from inside the catalytic converter - can this be right?

I also noticed that the vibration sound is heavier when turning towards one side - and it has nothing to do with engine revs as its still there if i turn the engine off while running.
I can only hear it over speeds of 35mph or so (not at lower speeds) but it increases as the speed increases almost like something is vibrating with the wind speed.

I did notice a few new rust holes in the muffler but i dont think this is causing the vibration as its still there when the car is running and the engine is off.

any help would be appreciated and thanks in advance.

 

additions - my tires are fairly new , they have about 6k on them.

The vibration is heard not much felt in the handling of the car - it sounds like something is resonating and I am running on the side of the highway all at the same time ,
the car doesnt shake or anything , just that sometimes the vibration is bad enough that it causes other things to vibrate in the dashboard like things in the ashray or anything not tightened up.

 

Hard to diagnose over the internet. If you can duplicate the vibration while the car is sitting still, make it happen and have someone try to find the source.

 

On my wife's civic, the heat shield above the exhaust pipe was corroded enough to come loose in a couple places and was sitting on the exhaust causing a nasty rattle. I just removed it - which was a pain because all the bolts were rusted so bad I had to tear it out. Glad I'm out of the rust belt now.

Anyway, just an idea.

 

I can duplicate the rattle by banging on the exhaust at the catalytic coverter , i dont know what the heat sheild looks like so I dont know what to look for.


The vibration however cant be dupplicated when the car is sitting still. I just noticed on my way home that it almost dissapears when I make a right turn over 20 degrees. but is there while I turn left or move forward. Its also only noticable when I am moving over 35mph.

 

the rattling could be the heat sheild...i had the rattling noise too....sounds like marbles in a metal can.

it is located underneath the car, roughly where your armrest is (center console)....some ppl just take it off...but i just wrapped some wire around out it to stop it from rattling.

 

Can also have rocks in it. DONT take it off. You risk a car fire if your exhaust ever overheats. If it aint falling off and is just rattling, either ignore it or get it fixed.

 

yea, i had that too... i just ripped it off.... problem solved

 

OK Back to the vibration - Its also more like a loud Buzz accompanied with a vibration like that of a massage pillow, anyone think that it could be something scraping against the tires when I get to a certain speed?

 

sounds like it is the cat. I had that same problem with my cat in my old car. I also just ripped it right out and replaced it with straight pipe. (I don't understand that 'fire in the exhaust' thing) With the car cold, get under the car, and bang on the cat with something, if it rattles then obviously the comb inside the cat has disintagrated and has broken apart. Either get a new stock cat, a high flow cat, or run straight pipe.