2010 5.4 hard to find exhaust leak
 

I have an obvious exhaust leak sound on the left side that just started at 180,000 , does the Pfffft type tick under hard acceleration, from standing or on the road climbing a hill with the trailer,(ETC) , (Sure does not sound to me like a cam Phazer tick which is more metallic)
I climbed under with it running cold and felt around and cant find anything ,
Cant see any broken studs but the leak is not easy to hear at idle or in neutral rev. ,
cannot see any holes between manifold and cats
Checked all the spark plugs and none were loose
seems to definitely be coming from the left side
has anyone had a similar situation and solved it ?

When the engine is cold, stuff a rag in the exhaust pipe and start the engine. Crawl underneath and see if you can hear where the exhaust is leaking or where it is loudest. Exhaust manifolds are not uncommon and unfortunately are not fun to replace. See if there is a lot of soot anywhere, usually a sign of a leaking exhaust.

I second a warped/cracked exhaust manifold. On the 5.4, the pass side is usually the problem child, but either side wouldn't surprise me. If you need a new manifold, spend the money for a genuine Ford part. Dorman replacement manifolds have a rather poor track record. I think the Ford part comes with studs and a gasket.

I took it to a muffler shop and they found it right away. Broken headerstud. They ordered a stud kit and gasket Took it in at 8 and they had it done at 1pm . . The surfaced the original manifold and had to remove one broken stud and replaced all.. Charged $375 . worth it to me because it probably would have took me 3 days of hatin life

I appreciated that they checked the manifold and reused it instead of automatically wanting to go with new one They said they have better experience with the original manifold than new ones.if it isnt cracked Said cracking is usually caused by heavy hauling up a grade until it is glowing red and then stopping suddenly and shut it off without idling down but the stud problem is a design flaw (8mm should be 10) or bolt quality. Said they do about 4 a year on f150 in this year range common known issue, usually passenger side, said passenger side was probably already been done

2010 F-150 5.4L with 212K miles right side has a leak for about a minute on cold start up but then I can not hear it. I will do the rag test when the weather is better. The general manager of the Chevy dealership pointed out the leak before I bought it.