The muffler fell of my 1997 4.6 at 138,000. The exhaust pipe fractured through just in front of the muffler. I spliced in an adaptor piece with clamps and everything was fine. Now it is getting noisy again but not at the repair. The noise goes away after it warms up. I haven't been able to find the leak but I suspect it is at the manifold to the head. Does anyone know of this problem and what is the cause and what is the fix?

 

Exhaust leaks are easier to see in cold weather. If it gets below 40 F or so you might be able to locate it by looking around after it warms up. Doesn't help if you live in Florida though.

 

Check your exhaust manifold studs on both sides, rear cylinder. That is what mine sounded like until the second stud broke. Now just tat tat tat all the time. Gotta get that fixed.

 

blown plug. some say you can hear a slight tat tat tat before it happens