F-Body Europe

I have had this sound for a while and am finally just sick of it. After I get on the gas if I let off it sounds like the car is back fireing (and let me tell you somthing nothing impresses people more than a car that backfires!). I scanned the car with my Snap-On scanner and found no codes..... but when I checked the data flow stream I found some funny numbers...... my MAP (manifold absolute pressure) is supposed to be from 3V to 5V and I only have 1.31V? I checked the intake for leaks (did the ol WD-40 test... the engine is suppose to rev up if the WD is sucked in by a vaccum leak) and nothing happened? What I am wondering if this noise is supposed to be a normal thing or somthing I should be worried about..... also if there is anything else that could be causing it. I was also told to change my cat's over to free-flow's to lower the back pressure in order to stop the noise..... Any suggestions would be appreciated! Thanks all!

My car backfires some times too.....
sure its not vibrating on a cross member?

does it sound like this? http://us.f1.yahoofs.com/msgr/steven_ma ... _DlbtiK1cq

.....just kidding but click it anyway my car with its new open headers

Jr
If you are not losing any power I wouldn't worry to much about it. Mine does it all the time.

All that is basically happening is the unburned fuel and gases are combusting in the exhaust.

Mine pops like crackling on the over-run.