Yesterday, I started my truck, after it had been sitting for a few days. So, it was cold.... per say, although it was 106 degrees here yesterday. And for about 1/2 of 1 second, it made this loud, raspy growl, which sounded like I didn't even have a muffler !?!? Then, immediatly, it completely quieted down to the nice, low rumble of my true dual Magna Flows ?

It was of such a short duration, that it was hard to try to figure anything out about the sound.... but I'm about 90% sure it came from the exhaust.....

Hmmmm.
Anybody have a clue what would cause this ?

Fish

 

could be from your truck sitting for 2 days. i dont know

 

i wouldnt worry about it unless it happens again and actually causes a problem. may have just been the pcm adapting to the operating conditions.