Sometimes a plugin acts up and is lagging the server to hell without giving any errors.

Even when you type "o.plugins" it shows a very low hook time.

I had problems with the newest version of AutoDecay lagging my server to hell, did couple of plugin reloads, server restarts but it kept on happening. Then I deleted all plugins to see if it was getting better and it was which confirmed the server being fine. Then I started adding back most important plugins, and it was still fine. Then i started adding back all plugins starting with letter A and work my way till letter Z. Once I added all plugins starting with letter A the lag started happening again which made me find the cause of the issue which was the newest version of that plugin.

All this caused alot of pissed off people (server lag, restarts, plugins temporary being disabled) all to find a single plugin.

So i still do not know why this was and I very much like to find when a plugin causes lag in the console. Is there any way of setting this up or a plugin perhaps that will give warnings in the console when a plugin gets laggy?

If a plugin is taking an excess amount of time to perform something, a hook warning will generally be shown. There isn't really a sane or reliable way to track down which plugin may or may not be the actual culprit of server performance issues, especially since it could be multiple contributing factors, not a just a single plugin.