Somethings F'ed up. 650 RPM's is way off.

 

What is a normal rpm?

 

Did it miss before you changed the plugs?

 

No miss before or following Motorcraft plug change.

 

730 rpms @ warm idle is perfect. Between 700- 750 is considered normal.

For it to idle that low there's probably an obstruction. Could be as simple as a dirty air filter and MAF.

A vacuum leak would cause a high idle.

Also, being that it's idling the way it is, -the EGR valve is suspect. That could be because of a bad EVR or a partially stuck EGR valve. To cause that low of an idle, it would have to be one or other.
I take that back, it could easily be the converters. They could partially plug and cause those problems. I suppose you could have a bad PCM, but I've never heard of one causing your symptoms.

 

Vacuum leak is was causing my strange idle at 650 rpm. It was not giving a code. but after looking at every hose under the hood I was find the leak. after i spliced the hose back to where it connected it was a instant fix.

 

Never heard of that, - doesn't make sense. Which line was it? What color?