I have a 2004 v6 3.9L Mustang with the only added mod of a cold air intake(1yr old) with up to date oil and maintenance.

I was driving down the highway yesterday morning with my car acting perfectly normal, then all of a sudden i heard my car go from quiet to a roaring motorcycle type sound. I first thought it was a blown head gasket but noone else has a loud sound like that when I searched on google and no smoke is coming out of my tailpipe. Everytime I step on the gas even a little it roars like a go kart and it has a purr of it when idled. Has anyone ever heard of this before and if so what is my problem?

Thanks.

 

if you post a video of your car it would help us help you

 

The passenger side exhaust manifold could have cracked. Did the sound happen after you hit a bump?

 

ill take a video and upload it. I didnt hit any bump, I was driving 65 down a highway and all of a sudden it just started roaringlike a motorcycle everytime i hit the gas. When i set the cruise control its perfectly quiet

 

Sounds like a crack/hole in the exhaust manifolds. At an idle it should sound like a ticking.