Throttle linkage issue causing high idle.

[wzuccarello]

I recently found this picture here and I'm having a problem here that is causing 2000 rpm high idle with my basketcase 2018. Previous owner messed with linkage, causinghigh idle.
On my other rocket which runs fine there is a slight clearance where the green circle and I can push the lever with the roller and feel a little slack before the throttle plate moves.
On my 2018 there is no slack here and it seems to be holding the throttle open slightly.
I have adjusted the sync screws all over the place and can't get the slack there like that my '05.
I do have the ecuTune hardware and software to use but waiting on a new starter before I can fully use it.
I don't know who or where the post with this picture is and I would love to find it again if anyone could help.

 

[Kevin frazier]

If you post some pictures of yours someone will probably chime in if thats your problem. So many times a high idle is stepper motor or tps, you mentioned you have adjusted the sync screws all over the place and cant get slack. Are you talking about the push/pull 10mm nuts used to get proper push/pull. Gonna need pictures and you should hook up that tune ecu and see what them throttle bodies are running at. Good luck

 

[wzuccarello]

If you post some pictures of yours someone will probably chime in if thats your problem. So many times a high idle is stepper motor or tps, you mentioned you have adjusted the sync the stepperscrews all over the place and cant get slack. Are you talking about the push/pull 10mm nuts used to get proper push/pull. Gonna need pictures and you should hook up that tune ecu and see what them throttle bodies are running at. Good luck

Ok, I found the problem!
The inner and outer throttle bushings above the stepper were fused together.
They are supposed to move separately very slightly and have a little clearance about 1mm in the end plate dogs, that you can feel when you push the lever with the roller, and spring returns the slack when you let go when bushings/shaft are not stuck together.
This joint was frozen with all the slack to one side of the dog plate and keeping the butterflies open enough to idle at 4000 rpm!
With plenty Kroil penetrant I worked the slack booth ways with needle pliers for a while and eventually the throttle spring would return the slack to one side normally, allowing the butterflies to completely close.
Got dark on me before I could adjust sync tonight.

 

[wzuccarello]

This also fixed the stepper adjustment issue.