Golf: Iron swing is okay. Wood swing is horrible. What's up?

Your swing shouldn't change, it's just the length of the club that changes. Low and slow when taking the club back and accelerate through on the down swing. Transfer your weight to your left side at impact. I like the reference of skipping a rock across water in the down swing because the motion is about the same. Give that a try and hopefully that helps you to improve. Another thing to try is to not grip the club so tightly to ease the tension in your muscles. You wouldn't believe how much of a difference that makes.