Nissan Repair: Exhaust leak, flex pipes, muffler shop

Question
I have a 1994 Nissan Quest GXE with a manufacture date of 11/93.  I have just replaced the front exhaust manifold gasket and all studs and nuts, but i cannot find my exhaust leak.  I think the flex pipe in the exhaust it leaking as the van is very loud when its given gas but idles fairly quiet.  my mechanic says the manifold is not cracked as he just checked it today.   Is it possible to replace just the flex pipe piece and how would I go about doing this?  thank you.

Answer
Dave,

A good muffler shop will have flex pipes that they can weld in or you could purchase the exhaust that has the flex joint as part of the pipe that connects the system from the Y pipe to the converter.  Your choice so check out rockauto.com or courtesynissan.com on-line to save some money.  Otherwise a good muffler shop can do the work.  Also, they can tell exactly where the leak is.  I ahve seen a manifold crack where it is very difficult to find...