Hi guys, I have a sort of buzz noise which I can just hear over my aftermarket exhaust which is loudish!

Have had the car on ramps and couldn't find anything loose at all.

It sounds more from the rear than the front and can only be heard under full throttle, part throttle I can't hear it. Whilst on the ramps we applied the throttle to 3 to 5.5k and couldn't hear anything rattling at all, but it is more noticeable with the window down when driving..

It also only occurs between 3-5.5k, although exhaust noise could be what's drowning it out after that.

Any ideas?

Thanks

 

I just replaced my catalytic converter, the core broke lose from the housing and would rattle/buzz when I lifted off the gas. It also took out the seconday O2 sensor, that's how I found it. When I removed the O2 sensor from the cat I could move the core around.

 

Ah sorry should of mentioned I don't have a CAT!

 

Then maybe something inside the exhaust has broken loose. Pretty common with some of the systems.

 

It's only a month old, we did give it a hit and nothing sounded loose in that department, are there no heatshields at the rear?

The noise is at the same rate as the exhaust noise.. If that makes sense.

 

It's a little work but if you cannot find the rattle, you may try putting the stock exhaust back on just to check. Did the rattle start after you put on the new exhaust?

 

Yeah could try that.

The noise used to be Distinctive and was only for a split second, now the noise has got quieter but over a longer period.

The car has been to the bodyshop and had the quarters sprayed so they're perfect and that's it.

Thanks