This is a really dumb question and I am embarrassed to ask it. On a 97 f150 4.6, what is the purpose of the black plastic lower intake manifold? I am replacing a front timing cover and was checking underneath the metal manifold. I saw what looked like pieces of broken plastic in the valley at the back. Is it possible the plastic lower part is breaking up and the truck still run?
Like I said, a dumb question. I am not very knowledgeable on how this motor operates, but am mechanicaly inclined so I could remove and replace intake if I have to. Truck is driven less than 1000 miles a year and just in town so not willing to put a lot of time, effort,or money into it. Just looking for information.
Thanks.

 

Since you see "something" you need to investigate and verify what it is and where it came from.

...Will it still run? Anything is possible....but not likely it would run correctly.

 

...

 

What the Sam hell you doin Brew?
With the valve body and intake plenum on the shelf at the same time?
Looks like trouble

 

There was a little trouble actually, had to make a pressure plate. I destroyed the first one. Drilled the holes a little big. No problem , fabed up another



The intake was a P&P. gasket match and knifing job in the works.

It was all fun, except for doing the trans twice.

 

I'll take a guess. Intake manifold on these will fail over time. That COULD be the issue and, if it is, NOW we be a good time to replace it (sadly, they only have a Dorman ones now that kind of suck but they seem to get the job done.) If you noticed antifreeze in there too, that's probably what's up.

See https://www.f150forum.com/f6/5-4-coo...nifold-318972/

 

Didn't some of the F-150's from this era come with "insulation" on the plastic lower intake manifold. Supposedly to "soundproof" it?

I thought I had previously read about that deteriorating and falling off. Maybe I just haven't recovered from last summer's intake saga.

Don't see how the truck could run if there were significant pieces of the intake gone.

 

Actually yes.

An air gaped Insulator.



Not sound proofing but a deterrent to heat soak. They fall apart eventually.

Soundproofing was a silencer inside air filter box/TB tube. Induction silencer.

 

More pics including the 5fours IMTV, tuning valve.



My old 98

 

Nice! I've never seen a drawing or a photo of one before this.