Pete,
I have had similar problems with my old three wood in that I struggled to get it going from the fairway / semi rough.
Basically my wife bought me a Cleveland HiBore XLS for my birthday last year and slowly but surly my play from the fairway (not that I hit it that often) has become better.
I attribute this to the smaller head which makes it easier for me to hit off the deck as apposed to some of the larger sized heads currently on the market.
In saying that the only downside to this club in my view is that I find it very difficult to play from off the tee as the head is quite a bit smaller that my driver.
What type of three wood are you using at the moment?
I would suggest you take a trip down to your local pro and try out some three woods which differ in head size and see what suits, failing that maybe a couple of lessons would help.
Kind Regards
Dale Strachan