Exhaust Noise?..help Needed

Please cut me some slack if i ask any dumb questions..i'm new to this haha
I have an automatic 2002 GT with 107k miles on it. When i push hard on the accelerator i hear a very quick rattling/clicking noise before the deep sound of the exhaust. I can best describe it as a "schucking" sound. The noise can be also be heard continuously when i have my foot pressed slightly on the accelerator when cruising. The noise seems to be coming from the transmission/exhaust area.
The noise started to happen after i loaded my custom tunes from Bama performance. When the car is returned to stock the noise goes away completely.
I thought it may be a pinging problem, but i have put 93 octane in my car for the last two months on an 87 and 91 tune and yet the noise remains . I thought it may have been an exhuast leak, but the noise doesn't happen constanly just when you first press the accelerator.
Help is appreciated

Hey thanks for the help..im really not sure what bama does to the egr in the tune..but i will find out. I never really considered detonation because it's not really a pinging sound.

Heres a video of the sound when mashing the gas pedal. Skip to around 22 seconds in. Its a quick little noise that happens right before the exhaust sound. When in part throttle its the same noise just continous.

trinity_gt said:

The "marbles in a tin can" sound just after 22-sec is classic spark knock (detonation.)

Click to expand...

thank you very much!..i sent bama a new tune request and told them about the timing issue. Thanks for the help