I have an 89 TBI that i replaced the cat back on and replaced the damaged cat with a pipe. The exhaust leak is coming from the passenger side up near the manifold, but I cannot figure out where from.

The previous owner removed some tubing from the A.I.R. pump leading from the black box to the metal tube that runs behind the engine to the cat.

With the engine running I can stick my hand up by the Y pipe to manifold connected on the passenger side and feel some air, but I don't know from where. Its really loud when running and I can hear clicking as well. Pretty annoying.