I have this annoying rattle coming from my engine bay while driving. Every time i get the car up to 2500 RPM in 2nd or 3rd gear. When I am just accelerating through 2500 RPM it is a quick rattle, but when i am cruising at 2500, the engine makes a strange whining sound. The first few times I heard it I thought my SC was surging, but the boost gauge doesn't show any fluctuation. Strangely it doesn't make the same rattle while in neutral, so revving the engine doesn't result in the same rattle.
I had it in to the dealership and the tech insisted it was just the A/C lines rattling in the engine bay and wasn't worth fixing. Now 3000 km later I am out of my comprehensive warranty and this is starting to really drive me nuts. Has anyone had similar problems? Or recommendations on how to fix this thing?

 

I have the same damn rattle been looking for a while now but no luck YET

 

Make sure the Cat isnt hitting on anything , some one had a problem simular to this and thats what it was . I'd check that the heat shields for the manifold and exhaust arent loose too.

 

heat shield rattling. ac lines are rubber except for the union parts onto metal (and usually there are brakets holding them stable. get off your ass. jack up your car. crawl under that balt. shake the **** out of your exhaust and look at your heat shields ( thin pieces of metal around your catylitic converter or around anything that could melt because of exhaust temperatures ). if you cant find it like that, get a voulenteer to rev ur engine while you're under there listening for it. get a pair of mechanix/leather gloves so that when you hear the rattle, you can put your hand on it and try to pinpoint the problem.

i see it at work all the time, people run over something and bend up the heat shield and they end up coming in with a rattling problem. usually you can just bend it back, especially if you dont drive it in snow and its not all rusted up.

hope this motivational speech helped you out.

 

he beat me to it!!! ^^^

rattle almost always = exhaust system something or other.

 

Stuff something around your cai where it goes down through the fender. and eliminate that.

 

could be a bad resonator (sp?).... thats my problem pulled my car out of winter storage and it was fine at first then once i started driving it my resonator started rattling something fierce....

but like everyone said most likely an exhaust thing

 

as someone said...it's probably the heat shield on your exhaust manifold. You could probably rig something up to make it stop or dampen the sound if you wanted. Or you could just remove the heat shield temporarily (don't recommend leaving it off) and see if you still have the problem.