I changed the busted coil n boot but pressure still come's out from there why

4.6L ... Replacement spark plug most likely wasn't installed properly and compression is leaking by it! .. Spark plug has been *cross threaded* into the cylinder head.. Cylinder head, spark plug thread repair kit available and is usually needed to fix this problem.. 'IF' spark plug *thread chaser* doesn't work.

These engines also had issues with the spark plugs pulling out the threads when removed