I am having a difficult time understanding what is going wrong. I understand your frustration. In my many years of smoking hookah I have never heard of a phenomenon such as this. You say you get lots of smoke but no flavor
Obviously there is nothing wrong with the tobacco you are using.
It could possibly be your charcoal. If you are using the quick light stuff. STOP!!! This charcoal almost always alters the flavor of the smoke. I suggest using any kind of charcoal other than the quick lighting kind. Also be sure that your charcoal is completely lit. The best way to tell is if it is completely covered in white ash.
Another possibility is that something is wrong with the metal ball berring that goes in the exhaust valve. If it gets stuck you will get stale smoke, or if it is missing you will hardly get any smoke at all.
This may seem silly but I have known people that don't put enough water in the base. Be sure there is enough water so that the stem enters the water by at least an inch.
You may also want to try poking more holes in your foil if that doesn't work try poking less holes. I also fluff my tobacco every time before I place it in the bowl to ensure that enough oxygen reaches it. So that I get a more full and flavorful smoke.
If none of these suggestions work. My final suggestion is to forget everything you know about setting up a hookah and relearn everything. There are some great websites out there that have great instructions. I also have a section on my website dedicated to hookah. I even have a page about the setup process. I hope I was able to help, Good Luck.