On sunday , i put on a new universal catalytic converter (Magnaflow). Since then at around 3000 rpm's and higher i here a rather loud whistling noise. has this happenend to anyone else? im going out now th make sure everything is tight. I had to replace the entire system. Am I an idiot and put it on backwards??? lol idk

 

sounds like a leak. start er up. crawl under it and "cup" your palms around your welds (without touching) and feel for leaks.