115 Merc 4-stroke trim oscillates while trying to trim up

[Ron V]

Posting for a friend who has come up empty on troubleshooting this thing. 2017 Merc 115 4-stroke. When trimming the motor up while underway, the motor comes up partway and then won't go further, but oscillates a little bit up and down in one position. Dealer replaced the entire pump, so it wouldn't seem to be in there. Left it partly trimmed overnight and nothing bled down either. It appears to have three trim relays; none have been replaced yet. We were out on the boat yesterday and the trim gauge also went wacky. Anyone have any insight? I'm wondering if the gauge problem is related...maybe a bad trim sensor causing it to think that it is at max trim? Not sure how the system works or if any of it could be Smartcraft related. Thanks.

[Motv18]

Some have a physical limiter basically a port in the piston tube if you’re there on a transom that’s has a high angle. Trim extensions is about the only fix or wedges.

If not it it could be shock valve or other manifold things

Make sure the manual trim thing is all the way in.