Hey all - over the past week, my 2003 GT is making a strange noise when accelerating from a stop or at cruise. The noise reminds me of coins or bb's being shaken in a metal pan. Any ideas what this might be? The sound started after I installed a MAC H-Pipe, but I assumed it was a coincidence cuz I wasnt sure how an exhaust mod would generate this noise?

Any ideas?

 

Engine detonation possibly? What kinda gas do you use?

 

I use premium gas - 93 octane.

Heres a list of my current mods in case its helpful for any suggestions:

Magnaflow catback
MAC H-Pipe
C&L MAF
Accufab TB and Plenum
180 T-Stat
Predator "tune"

 

Predator "tune" ? Is that somethin' you did yourself and did this problem just start after the installation of all this stuff?

 

The Predator tune is the stock tune that comes with the Diablo tuner. Really this noise started after I put the MAC on.

 

Well since the exhaust is more free flowing now, you could be running a little lead so to that. You can either try backing the timing down a bit or turn up the f/p a tad if you have an afpr.

 

Are you sure everything is tight on the mid-pipe and you don't have a leak?

You might be suffering from some detonation. Install the stock tune and see if it goes away.

You can install that worthless predator tune again if you want, but if it happens again you should back down the timing.

 

It's probably just something loose unless it's a pinging sound.

 

Thx everyone for the replies

 

exhaust leak.