Omec

iTrader: (2)

im getting this weird noise at around 6,000 rpm right before its about to shift at WOT. it sounds like possibly the cat is rattling but im unsure. this has been happening since i bought the car and just now trying to get to the bottom of it. it only makes the sound at around 6 grand. ive never heard mild spark knock before. only MAJOR knock from a 4 cyl mustang N/A that someone at my work turbo'd w/ stock 14 lb injectors (or somthing real low like that). it hit 20+ lbs of boost. im pretty sure i know what major detonation sounds like now lol. anyways. ive installed a catch can to stop the oil injestion, tried switching MAF sensors, took the super chips tuner off, and tried a few diff types of octain booster. nothing has any effect on the sound. its still has the stock cats btw and only has 31,000 miles on her. anyone ever heard anything like this? im going to hook my scanner up to it this week end and see if i can get the knock sensors to pick anything up. it doesnt derate or anything so if it is knocking the sensors arent doing anything i would think. any help would be great.

thanks,
corey