1998 Dodge Intrepid

Is your steering wheel shaking?

Very Good as I am thankful it is not giving your steering stability any problems. A shake or imbalance that is an up and down vibration are or may be, Tires, wheel, driveshaft, or suspension part. In that order, I thank-you for your question and your response.
Maybe if you rotate your tires or do a visual on them, it can change the feel, and help locate the vibration. As the tires are being rotated, a good check of your front and rear suspension will show the problem. If you have just had any work done, the brakes are a possibility, but rarely do they(calipers) loosen up.
Hope you get it fixed, good day.