rattling when let off gas?

[my first 420a]

so when i let off the gas and my car is just coasting in whatever gear if my rpm's are above about 1500 it sounds like something rattles idk what it is but my first guess was maybe the exhaust is rattlin idk any ideas.

 

[silver bullit]

Exhaust/heatsheilds...

 

[->PrOjEcTGS<-]

My 3" exhaust rattles against my driveshaft. You might have the same problem. Update your profile so we know what mods you have.

 

[El Cuervo]

Yup. Most likely exhaust on heat shields. If your car is a 1gawd and 3inch or so exhaust then most likely is your heat shields. Usually this is on the rear last heat shield closest to the rear differential, some inches before the pipe makes a 45* angle or so. If the movement of the pipe is severe, then often it might bump against the driveshaft when making left turns. In any case, for the heat shields, just raise the car from the back and with a hammer or whatever you can find, try to straighten and or bend the heat shield more towards the chasis of the car. Separating it as much as you can from the exhaust pipe. I just did this today and it seemed to work very well.

jorge.

 

[El Cuervo]

For your driveshaft, you are going to have to either turn your flanges over or reposition your cat or test pipe. I had to have these re welded because I had the same problem when making left hand turns. It was the worse on rainy days when I would go throgh a puddle of water. I would get this weird and very hight pitch noise. It stopped after I would make a comeplete stop. But if its rattling when you barely acelerate or when backing out of a drive way slowly when you are barely releasing the clutch pedal, then most likely will be the rear part of the heat shield closest to the rear differential.

 

[->PrOjEcTGS<-]

It was the worse on rainy days when I would go through a puddle of water. I would get this weird and very hight pitch noise.

Yea, why is that?? Mine definitely rubs more and makes more noise when it rains. Weird... Mine rubs right where the DP meets the Test Pipe. That flange is just not positioned in the best manner. I'm going to take the whole exhaust off and grind down the flange so that it can't possibly touch the Driveshaft.

 

[El Cuervo]

Honestly I have no clue. Maybe resonance from the water splasing. Or the fact that it get all wet between the flange and the driveshaft. If anything, shouldn't it get quieter because of the water serving as a form of lubricant? I do know that it gets very loud and very high pitch. You might need to weld extra hangers to keep the exhaust from having all that moving. Along with truning or re-positioning the flange.

 

[TheBigPhantom]

Wow I have the exact same problem but it only happens when the car's under body gets wet...must have something to do with the parts being able to move more since they got wet...

oh and the sound can also come from loose connections in the exhaust flange to flange.

 

[my first 420a]

sorry about the pro not being updated, i have a 3inch downpipe that goes back into the stock exhaust im not running a cat or a testpipe. my guess is it is a heat shield or something. but could this possibly be the exhaust itself making a sound from going into the stock exhaust haha idk. its not causing any problems its just annoying as hell and people always ask me what the sound is and makes my car sound kinda janky.