When the car is neutral and I rev the motor, it sounds fine, no noise. When I shift the car into gear, I hear a slight rattling sound momentarily when the car is in the 2500-3000 RPM range. It sounds like its coming from the rear of the car (vs. the gearbox itself,etc). the noise doesn't change as the car moves up the RPM range (change pitch or rattle faster). Once the car surpasses this RPM range in each gear, the sound goes away. It almost sounds like there's something loose, like the exhaust or something. The car runs fine, tranny and clutch feel good. I'm not entirely sure it hasn't been there from the day I got the car 2 months ago and I'm just noticing it now.

I know it's hard to describe and tough to pinpoint, but any input would be helpful before I spend hundreds of dollars getting it figured out only to maybe find out its normal an just how these wonderful motors sounds.

 

Try banging gently on the heat-shields around the engine and exhaust. They are held in place by screws, which can come lose and make the kind of noise you describe.

It happened to me and, needless to say, drove me nuts before I sorted it out.

Another issue could be the metal screws that hold the upper part of the rear wheel arch liner in place. It can tap against the inside of the rear wing... again driving you mad in no time.

Good luck!

 

+1 on heat shields.
Good Luck

 

Excellent suggestions fellas...I'll try that, thanks

 

Ok so the inner fender liners were loose and I tightened them up. The heat shield above the motor wasnt loose but it is very warped and brittle. I manipulated it a bit to see if possibly it was touching the motor causing the sound. I haven't driven it yet, so I'll report back on whether we've fixed the issue. Regarding the heat shield, is it worth replacing? It's doing its job seemingly, but because of how warped it is, its cracked around where some of of the plastic screws hold it to the body. Can it be replaced without pulling the damn motor?

 

^^^ I had that problem in my 95 coupe and it ended up being rear fender liners. I slit some rubber tubing and ran it between the liners and the fender and voila!

 

Yup, sounds like a resonance issue. You get specific vibrations at different RPM ranges and it can cause rattles to appear exactly like yours everytime the engine revs in that range. If the noise isn't the heat shields or fender liners keep looking. You'll find it eventually.

 

Just drove the car and it seems like tightening up the inner fender liners helped but it isnt gone. Do you think that could be the culprit even though I don't get the sound when the car is sitting still and I rev the motor? It's only when the car is moving.

Any thoughts on the heat shields being the cause since they are warped and perhaps not as well attached as they could be? What about replacing the heat shield?

 

this thread is inspiring me to look for the source of a similar occasional rattle on mine ( i thought it was normal.. learning everyday.) thank you

 

Did you try looking at your muffler straps and exhaust clamps? May be a source if not tightened. Oh one more place in the back is the rear bumper support bars. They are directly behind the rear wheels inside the bumper. If your car is not too low, you can actually see them laying on your back looking up. Many of these rust and rot apart.

 

Good idea...a couple of days ago I was going across a steep upgrade and just barely scraped an exhaust tip...wondering if that might have loosened something just a bit...

 

I had a similar rattle. How are your trunk lid gas struts? One of mine was dead. When the engine lid was closed, it was loose in the brackets (no tension on it fully contracted) and would rattle at certain rpms... It drove me crazy for over a year. If one or both of your struts are weak, replace them.
Btw, I was only able to diagnose this as the culprit after standing in the engine bay with the engine removed and the lid closed... And then it was by accident. I bumped the strut with a screwdriver while changing the fuel filter and heard the familiar rattle...

 

Good call...I'll add the gas struts to the list of items to check. I'm still finding it odd that there's no sounds when the car is stationary and not in gear and I rev the motor. It's only when the car is moving do I gear it, that's whats making me think it's something in the drivetrain, but I guess it could simply be the dfferent vibrations caused when the car is shifted through the gears and its moving...

 

UPDATE: I had the opportunity to poke around the car today and lo and behold,the drivers side exhaust heat shield was very loose. I jacked the car up and I was able to reach the 2 nuts that hold the shield to the body. I didn't have to remove the tire. While I could reach them I also tightened up the inner fender liner nuts too. Took the car for a spin and I couldn't hear the rattle,so I think it's sorted.

Thanks for the suggestions fellas!