chris88z24

My 2007 Cobalt SS Supercharged makes a strange rattling/clattering sound when under load. It is most noticeable after the 1-2 shift, say around 1500rpms. When I press the gas, I hear a whole bunch of chatter and what almost sounds like whooshing air. The best way I can explain it is the way a dirtbike chain sounds when it is loose, combined with the sound of rushing air. It almost sounds like its coming from the intake, but I don't remember it making this sound and the clattering noise definitely isn't normal. It's been doing it for a while, but it seems to have gotten worse.

I've changed the timing chain tensioner and ensured that there are no exhaust leaks. I'm starting to think that it may be valve-train related, especially since the old tensioner practically fell apart when I removed it. My warranty expires in June and I already have the problem documented, but I was just wondering: Has anybody experienced anything like this before?

Remember, it's only under load - at idle, the only sound I can hear is the ticking from the injectors, which is normal. I can kind of hear a whooshing air noise at idle, but it's subtle and really sounds like any other car at idle, so I don't think that is a problem.

I also don't think its the catalytic converter as that only has about 10,000 miles on it (was replaced before) and the car makes a solid 13psi at WOT with the GM Stage II kit.

Any ideas?

Thanks for readin'.