As you guys can see, I don't really post here, but I do browse the forums fairly regularly. I tried searching for this problem, but didn't have much luck. I have a 2004 MT with about 70k miles on it. Only mods are a racing beat intake and short throw shifter. Whenever I'm pushing the gas in more than about half way and the rpms go over 4k, I hear a pretty loud grinding noise coming from the engine bay and it continues until I let off the gas. It doesn't make the sound in neutral or with the clutch pushed in so I can't pinpoint exactly where it's coming from, but it makes the same noise in 1st, 2nd, and 3rd gear (haven't really had a chance to push it that high in 4th or higher). It basically sounds like metal scraping on metal. I've used premium 93 octane gas ever since I got the car, and it hasn't been overly hot or cold where I live in Georgia recently so I don't think it's the standard detonation/marbles in a can issue. I also don't have any issues with gears grinding when up or downshifting, although 2nd gear is a little sticky. Also, I bought the car used, but the previous owner said the engine had been vacuum tested and passed when I bought it 2 years ago.

I'll likely be taking it in to the dealership soon to have them check it out, but wanted to see if anyone had any ideas since I'm sure they'll try to pass the blame of on something other than the car having problems. Sorry if this has been covered before, but I didn't see anything that resembled my problem in the searching I did.

 

I get something partially similar at 7800-9000 RPM.. Sounds like a light grinding sound.. I'd say short shifter perhaps? When it happens to me and I listen to it, seems to be resonating from the shifter (or below).

 

easy to check if it's the shifter. take it out and put in the stocker... should take all of 10 minutes. If the noise continues then it's something else.

 

I'm pretty sure it's not the shifter. It's definitely coming from the front of the car. I can also hear it much more clearly with the windows open which leads me to believe it's coming from under the hood. The grinding is pretty pronounced. It's not like something where you wouldn't notice it unless you're listening for it. I can even hear it over my 3000 watt stereo system at mid to upper mid levels.

edit: Also wanted to note that I replace all the fluids with redline at just under 60k miles, but haven't replaced any of the spark plugs, wires, or coils. Any chance that could have something to do with it?

 

mine did that when i bought it used with 30k, got my new tranny in, and the throwout bearing was covered in clutch fibers causing the bearing journals to just slide instead of roll, mine only did it with the clutch engaged. and considering where our clutch is, it could sound like under the hood.

sit in neutral and hold your revs at 6k, push the clutch in, hold for 2 seconds, then release the clutch fast (still in neutral). if the noise is there its the throwout bearing. if not, ignore what I say.

best of luck in catching the gremlins

 

TRY THE syncro's??