harmonic vibration at idle

[RickOTR]

I now have this harmonic vibration at idle that is driving me nuts and cannot find where it's coming from. I can here the catalyst inside the passengers CAT rattling around so I was wondering if that could be it. I can feel it through the steering wheel more when it's in Park than when it's in drive.

I'm wondering if it had anything to do with my mishap I had last weekend. read here http://www.explorerforum.com/forums/showthread.php?t=387780

 

[Runnin'OnEmpty]

The issue might be in the spool valve inside the
rack and pinion, or it could be the power steering
pump itself. You could try removing the serpentine
belt and see if the harmonic persists. If it goes
away, the problem is most certainly in the steering.

While you have the belt removed, try spinning the
PS pump pulley by hand, checking to see if it is
dragging or in a bind.

 

[RickOTR]

It turned out to be the Pinion preload was off causing the vibration through the steering wheel. I took it to the Ford Tech who works on my Ford GT and he said the Pinion Preload must be adjusted every now and then as the rack wears. I guess you learn something new everyday. The rack is still in excellent condition, so I'm lucky there. Unfortunately, I found out that the passengers side CAT is on it's way out as the substrate has come loose causing a rattle sound, but no CEL light light.

 

[Runnin'OnEmpty]

Good to know about the pinion preload. I guess after
a half million miles an adjustment or two is needed
sometimes...