When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Check the wiring around the headers make sure nothing is coming in contact with the headers. I would think you would notice that more than just during hard acceleration but it can't hurt to rule the simple things out first.
Are the headers newly installed? Reason I ask is because of heat wear in which gives off a smell the first few drives. Otherwise you may be getting some "blow by" into the intake, Common on the LSX series motors. Just toss a catch can in and call it a day