Would the pu bushes cause stiction on the post? I changed the crappy original rock shox one as it delaminated.
If the bushes wear play in the post is the usual outcome. The Rockshox bushes do fall apart, especially the lower one which generally wears out first. Is the post only stiff in one direction IE on the way up or is it also stiff to push down? What did you replace the bushes with can I ask?
I’m running through the things that spring to mind.
Pressure too low.
Friction inside the post caused perhaps by the bushes. (Never experienced this)
Too little fluid in the actuation circuit.
Poppet valve ports blocked or poppet not opening fully.
Problem with the handlebar button/lever not supplying enough fluid to depress the poppet.
I’d persevere with this, it’s probably something simple. I’ve acquired several of these post; all abandoned by their previous owners as written off. Main issues, Lower bush worn, Old model IFP passing, Bottom circlip rotted away & needing bled.