There's one difference here between the two shots IMO; expectations. If I hit 5 drivers off the deck while I'm dicking around at the range and I expect them not to do anything but 2 or 3 get off decent, suddenly I feel like I'm hitting 80% of fairways and hitting it better than off the tee. If I hit 5 drives off the tee and expect them all to be perfect but I mishit 2, Then I feel like I'm hacking it up because the ball's on a tee and I want a perfect shot from a perfect lie. I think that you are taking the correct course of action by trying to fix your tee shots, but being able to hit from the deck isn't a good excuse because that's a preposterous shot and it doesn't really help anybody's game. Basically if you're being realistic, the thread title should be "Driver Trouble- tee it up- Oh no?".
Not saying this to be negative but I'm reminding you that hitting driver off the deck is a desperate play and working on it or being good at it only distracts from the problem. We have a couple guys on here that get tons of great advice but have too big an ego to actually work on anything properly and just keep making excuses for why they don't get better, so I hope that you have the right attitude for the challenge.
(Same thing with people who can hit a 1 iron "great" but still struggle with clubs that matter. I've been guilty of that too. Hit the 1 iron all day; you'll never get better unless you work on your problems.)
Anyway, I suggest you give this thread a read for starters: http://thesandtrap.com/t/44307/hitting-up-or-down-with-the-driver-in-an-inline-pattern
It has lots of useful information about setup and a few key concepts about hitting good drives. Obviously if you play to an 8 your swing must have a few redeeming qualities, so finding a setup and swing pattern that allows you to smack the ball with a bit of confidence on the course will do for starters, and you can make adjustments over time as you adjust.
My one tip would be to play the ball forward and make sure to hit the ball on the upper middle part of the face. If you are hitting the ball off the deck with any crispness then you're probably playing it behind the low point of your swing like an iron and hitting it very thin, which is a treacherous but sometimes playable shot with the driver. Hitting that part of the face increases the effective loft, maxes ball speed, and reduces spin, all of which can fix a lot of things.
Lastly, I second the advice to make a swing thread (http://thesandtrap.com/t/38240/my-swing-video-threads-rules-please-read) There are good instructors here and they are capable of helping anyone play better.