heres the deal, it literally sounds like something is grinding, like my muffler is scraping across the street. however, through a few test drives ive taken notes that might help you guys figure this out.

it ONLY happens when i accelerate around 2000 RPMs.

-does not happen when idling
-does not happen while turning
-does not happen while shifting gears
- shouldnt involve suspension
-does not happen during BRAKING

do you guys have any idea what it could be? it ONLY happens around 2000 RPMs while i give the car a little gas. im completely baffled as to what it is.

some notes about my car
-my headers are megan, so there is high resonance
-im due for timing belt change (103k)
-my alignment is off

PLEASE HELP!!!!

 

1 of a couple of things..

you may be mistaken for a tin rattle.. which would be the heatshields rattling.

or it "COULD" be your water pump bearings..i HIGHLY doubt the water pump bearings have dryed up over 100k miles. I have heard maybe 3 cars with dry pump bearing that rattle and make a grinding sort of noise. so that's a rare case.

it's probably your heatshields on your catalytic converter or your b-pipe.

good luck..
come back if you find out that it's not your heatshields and your POSITIVE.

 

I'm not sure about this, but it could be audible brake warning indicators for the rear rotors, but it should do that at all times - so nevermind. by not fully reading the thread.

 

Rattles under the car are often a result of "resonance", the vibration/frequency your engine or chassis makes at specific speeds.

You mention it does not happen at idle, but, Try this... put your car in neutral or park while on a flat lot and rev the engine to 2,000RPM or just past. If you hear the "grinding" or "rattling" as the engine passes 2,000RPM you have now identified that it is related to engine speed and engine vibrations, not the driving speed or road conditions. If this works you can also use two people to pinpoint the noise. One can look under the car/hood while the other works the throttle.

If it is happening while driving does it happen in all gears? Does it happen all the time or just sometimes? If you cruise at 2,000RPM can you continuously hear the noise or does it come and go?

Just a few things you can try out...

 

I vote heatshield on your cat. My car made similiar sound also rattled when I turned engine off. My heatshield had two bolts rusted off so I just ripped the damn thing off and now there is no sound. If you do this just be careful not to park over any dry leaves or anything flammable as the cat gets very hot.

 

 

I wouldnt worry as much about leaves, i'd worry more that you ECU is right above the catalytic converter inside of the cabin.