Sorry for the bulk just trying to give everyone a little help.
These problems have eaten me alive in the last few months.
Best rule if you have a 4.6 with over 125000 that has a Plastic intake Manifold get ready for some Cracks. If you are lucky it may go 300K.

 

I respect the help factor . Format needs a bit of work .

 

I need tylenol...

Thank you for your obvious expertise. 150K would be great! It's only got 62 on it now!!!

 

Check for the moisture on the plug its cheap and can save you much time.