Emergency-Plenum making tapping lod pop

I originally posted here with an engine my landlord having anti-freezed my engine.

Last night, while climbing a hill on the way home, my engine then started making a loud popping sound, like the previous tapping, but now tapping. The engine has dried oil outside of it. I checked the spark plugs, all are just fine.

But, I touched the plenum while it was running, and something is tapping back against it on the passenger side.

What is going on? How do I fix it?

I'm stuck at a friend's house-car runs, takes longer to accelerate. makes pop sound, instead of clicking.

The 2000 Windstar has a 2 part upper intake manifold.
I only know what I have read in posts here because my '96 had the old 1 part unit.
What I have read is that the inner part of the upper intake manifold can come loose and rattle.
This applies ONLY to 1999 model year and newer.

Sadly, my pictures will be of NO help to you.

The other thing that does come to mind is a broken valve spring, which several people have reported to have had happen.
I recall reading a post or so about a fastener coming loose for a valve also.

The first problem would not cause any problem with performance, but the 2nd one would.

Here is a video with the engine and noise. I spoke to my neighbor, he stated the noise and vibration can be from anywhere, so next I'm doing a valve compression check, will post results here.

If nothing happens, I'll take the front valve cover off after that!

http://youtu.be/01T1R2Aecdg

What do you think?

I don't know what a broken valve spring sounds like but I don't think it's your problem. The engine seems to be running OK.

I believe you might have a problem with the harmonic balancer, specially if the noise is more noticeable on the passenger side, it has rubber around of it. Remove the serpentine belt , if you can, and take a look at the biggest pulley (crankshaft puley) and look for missing rubber, pieces coming off, cracks, etc.

Oscar.