Elevators are always the same speed
The maximum speed is useless as people can set it to 10000 and it will take it.  No matter what speed I use, the elevators are the same speed. maybe I'm missing something, but this doesnt do anything.  

Hey Codepimp1234,
Couple things, make sure you have the latest version of the plugin v1.0.4.

Also, there are two permissions...

elevatorspeed.use and elevatorspeed.admin

if you give players the elevatorspeed.admin permission, it will ignore whats in the configuration.  If you grant them elevatorspeed.use it will check the configuration for the maximum speed and enforce that.

I just tested this and it seems to work fine on my end.

To begin with, I don't speak English, so I rely on translation machines.

Running /liftspeed <number> temporarily increases the speed, but appears to be reverted to 1.5 in an instant.

For example, if you run /liftspeed 10, then at that moment /liftcheck will show the speed as 10.

But when you do another /liftcheck when operating the elevator, the speed is 1.5.

This is the video I tried.
https://youtu.be/yacFhGGZyYE
That is strange. I have never seen that issue before. I tested it both on my development and production server. It works fine in both cases. Do you have other elevator plugins that might be causing a conflict with my plugin???

I suggest deleting any other elevator plugins and make sure you are using the latest version of my plugin and see if it works.
That video shows the elevator lift has a counter on it, which likely means Better Elevators is being used. The default configuration of that plugin overrides speed whenever the lift is activated (in order to support dynamic speed). Better Elevators has a config option "EnableSpeedOptions" which can be set to false to prevent that behavior, so that other plugins can control speed.
Lol thanks White!
As White said, I used BetterElevators.
I made sure that /liftspeed works properly by setting EnableSpeedOptions for BetterElevators to false.
Thanks for the right advice.
that explains my issue.   thank you Lincoln and WhiteThunder !