I don't believe there is a gMail Storage app; I've never seen it.
It's not an app you can start like a normal app ... I think it's a background app. If you go to Settings-->Applications-->Manage Applications, there are "Storage" apps listed with several actual apps. For example, there is a Calendar Storage app (background) along with the Calendar app (which you can start).
What do you mean when you say that gMail won't sync? Are you not getting mail on your phone? Or are deletions not syncing?
I set my gmail to sync/refresh manually. So when I check my gmail, I manually refresh to see the new mail. Now, when I touch "Refresh", nothing happens. In addition, if I change my sync settings to auto, still nothing happens. When I cleared all my gmail data (so there is no longer any emails on my phone), I can't download any mail, new or old, manually or automatically.
You don't mention which app you are using to read gMail; if it's the stock gMail app, you should go to Settings->Accounts & Sync->Google and make sure that Sync GMail is selected, and that no error message is displayed. You can sync it manually to see what happens.
If you are using another app with which to read gMail (as you might be, because you have it set up as IMAP), let us know.
I'm using the Gmail app ... not the stock Mail app, but I believe this is a "stock" Gmail app. If you go to Market, you can download/update it ... but I think it's the "official" Google Gmail app.
If I go to Settings-->Accounts & Sync-->Google and click on "Sync Gmail", nothing happens.
You should be using the GMail app, not the Mail app with imap. Thats why you dont have Gmail Storage.
Yep, using Gmail app and had been using it for about 8 months without any issues. I had it set to not automatically sync/refresh ... so whenever I opened the Gmail app, I would click Menu-->Refresh to download any new emails.
Thanks for the help ... hope that gives you guys some leads ...