Dan04COBRA

Does it happen in neutral when you rev? Are you using oil?

Also, 'fluttering' isn't a good way to describe the sound.

You could have something as simple as a bad plug or pack, or you could have a piston ready to break into 7 pieces. Please describe the sound better.

wildazme

the noise doesnt happen when you rev the car when its in park, it also doesnt really happen under light loads it only usually happens when you get on the gas. its hard to describe the noise, it doesnt sound like knocking. it sounds more like when a cat starts to break up and you have pieces sputtering around inside of it, the only thing this is from the engine bay and seems to be on the passenger side.

70 MACH I

Check for a stripped/loose sparkplug early 4.6 engines this vintage had this problem.
John

dvs_03gt

i think its because the flow air from the xpipe hits the stock catback and makes that sound. i have the same sound with my xpipe and cats. ive heard other gts with new catbacks it seems to elimate the sound?

wildazme

its not the xpipe because it happend even when the car was stock.

wildazme

well asked my girlfriend to try and describe the noise the cars making, she said it kind of sounds like dragging a metal hanger over cement.