I have searched the forum over and over, reading every *rattle* posting available, yet I haven't found one quite like my problem. I have taken my G to the stealership and had them put it on the lift, but of course they couldn't hear anything; most likely due to the fact that the suspension is unloaded and sets up different stresses and tensions for resonance freqs. I took the G out with the Tech, and then later on with the Master Tech, and could point out the rattle which they actually heard and agreed that there was something amiss. In the end, they sprayed some foam under one of the brackets, and turned the heat shielding differently at the beginning of the exhaust. Didn't eliminate the noise.

The set of conditions for rattle:

Bring the car up to 4000 RPM in second gear. Punch the gas, WOT or close, at 4400 RPM, and up if you keep going, you get a metallic rattle, not the tranny or anything, just from the center of the car under the stickshift area or a little to the driver's side. It isn't as high pitched as I would think heat sheilding would be (have an older Camry that has heat shield rattle) but still sounds like something along those lines. A bracket would be a good guess, i.e. thicker metal.

It will sometimes rattle when you take off in 2nd gear at a very low RPM and are giving it a good amount of gas.

Do I just keep taking it back to the dealership and have them eventually track it down? I got under the car and banged around for a while, but can't really locate the right sound, since 4400 RPM is wrapped up pretty high and parts are moving fast.

Any suggestions?

Thanks in advance -

hot_e-

 

Wow, that sounds real close to what I have going on... I put on some high-flow cats and that brought the required RPM down from 3.5k to about 1.5k. Now everytime I pass through 1500, I get the rattle - and it's really nasty. I thought it might be the mufflers I had put on not being able to handle the flow going through there, but now I'm going to tripple check before I have the guy replace them under warranty. The rattle almost stops once the exhaust gets pretty hot. It's terrible when I first light it up in the morning.

 

It does seem to quiet down a bit after driving it for a while.... although if you are driving next to a raised center median I can hear it loud and clear no matter what. Medians, walls, anything to get a reflection off of the sounds from under the car - this is by far the loudest it gets. It's just SO annoying when you are in 2nd gear and give it a kick to get past someone, or just for the hell of it, you can expect it every time... makes the car feel cheaper...

 

If our problems are the same, you have have a loose baffle somewhere in your exhaust system. That's why it is so hard to find. I have had this problem for a couple of months and believe me - everything - has been checked and confirmed tight. The baffle is the only thing left and almost impossible to confirm with the car on a lift because it only happens under load and higher RPM.

Yesterday, I had a little fun during a WOT moment and I think the baffle got stuck. The rattle stoped! I'm still going to have the shop replace those two mufflers just to make sure it doesn't come loose again but that pretty well confirmed it for me.

 

Almost sounds like a bad cat converter.

 

Anyone else?
If it is a baffle, will the dealership replace/repair under warranty?

 

Did you identify where is the rattle noise coming from? Is it the exhaust system?

 

i got the same problem after installing kin HFC..wouldnt you get a CEL if it was a bad cat?...im switching out my exhaust back to stock so hopefully that stupid rattle isnt there anymore..if it persists i guess ill bi tch at kinetix

 

bump...anyone with an solid answer?

 

^^^
for rattles that come after you install hfc, you should try putting on an ENGINE DAMPNER, most hfc are known to rattle cus of the heat sheild on them are so close to the underbody of our cars...

when you floor the gas, the engine twists and turns a lot(engine is connected to the headers, which is connected to our cats) and during all the twists and turns it moves the cats which in turn rattles against the underbody

 

i removed the heat shields...still there..im starting to think its a bad cat but im pretty sure i would get a cel..or am i wrong about this?

 

cats don't go bad very easily...they should be good for more than 100k

but like i said, a lot of peps have rattles after they install hfc...

you should try searching if you haven't already...

i'm pretty sure an engine dampner will aliviate your rattling

 

I've had a rattling issue that only occured during a certain RPM range. It had to do with the exhaust making contact with the body. To solve it, I took my car to a muffler shop, had the guy check the entire pipe line for clearance.

He welded in a few hanger to pull the exhaust one direction, problem solved.

 

It's not the cats... I put on HFC after the rattle started. HFC just changed the RPM range the rattle occurs at.