Ive had to replace my passenger side exhaust manifold three times in one year. Any idea on what is causing this? I have a 2009 with the 5.4L with 82,000 miles. I've heard horror stories about the 5.4 but my Truck runs great other than the chronic manifold issue. 2 of the 3 time it has gone bad I was towing. Any ideas will be appreciated.

 

Do you have an aftermarket catback justom fabbed by a shop? Somet8mes they can make things strained and overtime the tension in the exhaust and heat can make things fall apart.