I have an exhaust leak on my 04 stang it only leaks when cold is it a gasket or a cracked manifold , any advice please

 

Sounds like a gasket if i were to guess, metal expands when its hot, so the manifold itself might be closing the gap a little bit as they heat up. I think that these cars have a problem with the passanger side manifold going though.

 

Condensation from the A/C drips onto the passenger side manifold causing it to crack. Ford has never fully owned up to this and never issued a recall.

Your options are:
Get a new passenger side manifold and have a shop fabricate a shield to protect it from the drips.

Or get headers and have a shop fab up a shield (Though not needed as much as with the cast manifold.)