Appreciate the find Kevin, although it wasn't the Throttle Drum Screw that I adjusted it was the Fast Idle cam screw that I tinkered with.
Over the past few months I've noticed a slight coolant drip under the Intake manifold. It was small, so I paid it no mind. Yesterday I removed the Manifold and plugs as part of my diagnostics. When I removed the #2 spark plug it was soaked in coolant. It sits almost directly below the minor coolant drip. This is observation #1
When I scanned the underside of the manifold I noticed dried coolant on either side of one of the hoses (source of coolant drip). This is observation #2
The leaking hose feeds into what appears to be a hydrolic component. When Coolant is cold (cold start) the plunger is in, as it warms up the plunger moves out and pushes on fast idle component, which in turn decreases the throttle drum. Problem is, I cannot move the fast idle cam by hand like I see people do in videos. This is observation #3
My conclusion is that the fast idle component (spring) is too hard for the plunger to move, which explains why it (the adjustment screw is bent again. Because the area where the screw is is very strong metal, the pressure built up behind the plunger must be extreme enough to leak from the hose, and possibly foul out the plug. Replacing the fast idle assembly is the obvious course of action, but... the assembly is hard to find and the spring for it is discontinued. Go figure!
The fast idle cam has two marks on it, one closest to you on the low side of the cam and one further away on the high side
With a hot engine, adjust the fast idle cam screw so that you are at the line closest to you. The cam should not be touching the assembly because you don't need fast idle with a hot engine
When warming up the engine it should be around the high side mark
I didn't find this info in the manual, I just figured it out myself
I also cannot turn the fast idle cam by hand on mine, I don't have a bent screw either
Does the plunger move at all from a cold start to a hot engine?
The problem sounds like either the plunger is seized or the spring area is seized not allowing the plunger to move
If it's seized in the cold position then there's your high idle problem (if you have one)
If you have a low idle problem then this is not the culprit because with a warm engine the fast idle cam should not even be contacting the throttle at all so even if it were seized on the hot position, it would not cause a low idle problem
The thermal plunger can be bypassed just FYI, loop the hoses together and eliminate all the related hoses and lines from the under side of the upper intake manifold
And then if you're concerned about cold starts I THINK the ecu should richen up the fueling at a cold start even with deleting the fast idle cam. It should see the low intake air temp and low coolant temp, and richen her up just with those on its own without the use of the mechanical plunger. Although I'm not sure how that would translate as far as a smooth cold idle
