'95' 5.0 won't idle

[prplhays]

Was looking to see if anyone had any ideas on a '95' 5.0 with 5-speed that won't idle. When at an idle, the idle varies from 800 down to 300-400 rpm and enventually it will die. Car also use an incredible amount of gas, like almost half a tank driving about 70-75 miles.
Car has 82k on it, drives fine and engine runs smooth and has plenty of power above an idle. Replaced air cleaner, plug wires, plugs, idle compensator, O2 sensor and cleaned mass air. There is an exhaust leak before the O2 sensor. Could that be the problem? No one seems to want to tackle welding it since it is in a difficult place to get to on top of the pipe. I was thinking about putting a muffler wrap on it to stop the leak just long enough to see if that's what's causing all the problems. Any help would be appreciated.