hey this is going to be really hard to explain ... ive got a 305 tbi and ever since i got the car theres been this weird vibrating/rattling sound that only happens when im either just idleing or stopped, and its usually only when my cars not heated up yet .... it sounds like its comin from something under the front of my car ... i thought it was either my cat or exhaust ... but ive since replaced both and the vibrating is still there ... someone said it mite be a heat shield, but i dont know ... like when im at idle i can FEEL it and it shakes a lil, but as soon as i put it in neutral it goes away ... it doesnt do it at all while im moving ... if anyone knows that the hell it is please tell me lol, i would love to get rid of this problem .... thanks Kelly

 

You're not alone, my friend. I've got the same issue but haven't crawled under it to check it out...too many other projects going on. I'm betting on the rear heat shield stuff by the gas tank or the cat heat sheild. I may just replace it with the Dynomax off my Iroc.

I'd have the ladyfriend start it up and put it in park and you crawl around under there and see what you find. Better make sure she's not mad at you before you take your life into your own hands, though.

Ed

 

Are you in gear when it rattles? It could be worn motor mounts.

 

Mine's usually in gear when I get the rattle, but it sounds like it's coming from the rear somewhere, back and underneath.

Ed

 

yeah its in gear when it rattles ... it wont do it in neutral ... but like i said it for some reason does it mostly when my cars still cool, once its hot it almost goes away

 

If you all have the same problem as me then it is the thing that warms up your carb

it is a little arm located on the left of the engine beside the exhaust manifold start the car and push the arm down and it will go away. i have to do it every morning

 

I HAD THE SAME PROBLEM.( 88 FORMULA 350). THE RATTLE WAS AT IDLE. FOUND THAT THE CLAMP THAT CONNECTS THE EXHAUST PIPE TO THE AIR PIPE TO THE CAT WAS LOOSE. THAT IS; THE CLAMP WITH IT BEING ON AND OFF LOST IT SHAPE. TOOK IT OFF AND NO MORE RATTLE. ALSO I HAD ANOTHER SPOT WHERE THE AIR PIPE CAME TO CLOSE TO THE FRAME UNDERNEATH. TOOK SOME RUBBER BELTING AND LOOPED IT OVER THE PIPE IN THE AREA OF CONTACT AND CONNECTED THE 2 ENDS WITH A "ACCO" TYPE PAPER CLAMP. IT WORKED. BOTH AREAS ARE NOW RATTLE FREE .