Those IDs are correct, so this is likely a workspace or project issue.
Let’s try something first:
1) Create a new web project: File > New > Project > Web Project. Create a JSP, do you get autocomplete ok?
2) Create a new web project and copy all your files from your problomatic project into the new project, now try autocomplete, did it work?
Also what kind of autocomplete are you trying to get, pelase paste a snippet of code below and show where your cursor is when you aer trying to autocomplete.