Exhaust Noise?..help Needed

[NinjaDude727]

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

 

[Mattstang04]

If you have a manual and you are shifting to soon or bearing to heavy a load on the engine for the gear you are in, the drivetrain may shake and emit some vibration noises. Hard to say without hearing the noise first hand. Could be a loose heatshield, worn bushings, worn exhaust hangers, etc.

 

[trinity_gt]

It definitely, to me, sounds like you've got an issue in the tune and what you are hearing is detonation. The fact that it goes away when you return the tune to stock tells me there's either far too much spark timing in the tune or there's something the tune is doing that is allowing detonation.

Q: Was anything done to the EGR in the tune? For example, was it turned off?

Detonation at tip-in (when you depress the accelerator) is classic symptoms of too much initial advance. Detonation occurring during part throttle suggests that the EGR has been turned off.

 

[NinjaDude727]

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]

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

 

[NinjaDude727]

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

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