Bicycle Tutor

I have Shimano Dura-Ace STI front derailleur and shifter. To shift from the small to the big ring, a lot of pressure and force is required to move the shift lever. After consulting with my local wrench, he suggested I replace both the cable and the housing. I did this with no improvement. I have also lubricated the dickens of all moving parts of the front derailleur. The cable is routed correctly through all the guides, etc.

When the cable is not anchored securely to the front derailleur and I apply just enough tension by hand to the cable to keep it taut, the lever moves very easily. Any ideas? Thanks!

I would have guessed that it would be the cables and housings. But you said that you already replaced them.
Can you post any pictures so we can see the problem? It sounds strange.