Vulcan Sticky Throttle

I've narrowed down a throttle which won't return to idle unless I let it snap back to idle to a sticky throttle. Does anybody know what internally to the throttle that might be causing it to stick once the underhood temp
reaches 200F? The vehicle is an 86 Mercury Sable 3.0. I've removed all the attached cables and it is indeed the throttle. I've subsequently removed the throttle valve which on this engine is the upper intake plenum and valve combined into one casting. Is there a common problem that you ford mechanics know of that I should look at? The needle bearings on either side of the butterfly look ok, and I see no reason for it to bind like it has been. One thing that ive noticed is that there is side to side play in the butterfly...is this normal?
Thanks
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Have you tried to clean the throttle body? An excess of carbon buildup in the TB can cause the condition that you describe. Additionally, the side to side play you describe indicates wear of the throttle plate, which is common with an 86 Taurus/ Sable. You can replace the upper intake with one from any year between 1986 and 1995.

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