Without seeing your swing, I can’t say anything for sure, but make sure you’re not moving the ball up in your stance as a reaction to teeing it up. Some players hit irons just fine off the turf, but move to a more driver like setup when those shots are sitting on a tee.

I'll make a wild guess. On the tee box some of us tend to think swing up like with a driver. That makes some of us set-up like we would with a driver. So how is that different? A little too wide of a stance, ball a little too far up in the stance and we might even add a little spine tilt indicated by our left shoulder being much higher than our right shoulder. Everything you want for a driver and nothing you want for an iron. So check all those areas and see if any of it sounds like you. Now, when you have an iron in your hand, set-up like you have an iron in your hand. Stance is a little narrower, ball is more towards the middle of your stance and…for the love of all that is Holy in this world...keep your left shoulder down man! No spine tilt on this shot at all! The spine stays stacked so you can hit down and through the ball. Good luck and play well!

Is this different from your normal fairway iron shots? In which case, are you teeing up your irons too high?

Irons should be teed up only barely above the ground. It's there to try reduce any grass getting between the face and the ball.

Sounds like you're getting too steep and forgetting to rotate through the shot. Work on not only rotating your shoulders on the backswing, but also the follow through, making sure chest faces the target after impact.

How do you hit it on your approach shots from the fairway? If you like the yardage, don’t tee it up on the tee box. Play it like you are on the fairway. Just put it on the ground and fire away!! Or if you still feel the need to put it on a tee. Take a practice swing at one of the many tees no one picked up off the tee box. When you feel a good swing. Step to your ball( I always think, pop the tee out) and swing away. Don’t forget have fun!