I have a 2003 F250 XLT Super duty 5.4 RWD A/T with 170,00 miles. So There is this strange
noise coming from the middle of the intake manifold area the only way I can describe it is
that it sounds like an exhaust tick. It has the deep intake manifold so I don't know if it
has a flapper in side the middle of it also cyl's 1,4,6 and 7 have hardly any change when
I individually disconnected the injector plugs to each cyl. The compression is okay in all the
cyl's and I also have two lean codes for bank 1 and bank 2.
Seems like a bad intake manifold any other Ideas out there?

 

Definitely sucking some air......might want to google 5.4 vacuum leak and narrow down some of the usual suspects.

 

I YouTube searched but could not find anything like this noise. Smoked test but came up with nothing. I google it and see what I can find.

 

exhaust manifolds playing games with your mind

 

I had to replace the intake runner control motor in a 1997 f-150 with the 4.6 I had for a similar problem. It is a geared motor with a plastic flapper that changes the intake length depending on rpm.

Just an Idea

 

Thanks fordmerc yeah that is what I was thinking just wanted to get other inputs. I'm going to remove the intake manifold this week. I'll keep everyone posted when I fix the problem.