I got this really bad exhaust resonance at about 1900-2000 RPMs on my 02' V6 5-speed, sounds like a heat shields loose. I had it jacked up in my drive and tried to check my heat shields, they all felt solid. I couldn't really rev it and listen (dam drive by wire) up top. I took it to the shop and had it on the hoist with a guy revving it in that range. We first thought it was inside the transmission but it was not vibrating to the sound, the crossover pipe was vibrating with this resonance and it seemed as though it was coming from inside the pipe itself!

Does anybody know what this is? Its sort of a really loud version of a grand prix resonance...is it just the nature of the 3800 Series II?