Shimmy/shake in a '92 Chevy 1500

My 1992 Chevy 1500 2WD extended cab, long box with 80,000 miles has a fairly big shimmy or wobble that is felt in the steering wheel and front end. It happens as soon as you start driving but will go away at 60mph and above and then it seems to drive just fine. I had the wheels balanced and I thought that helped for a little, but it didn’t. Everything seems tight up front. Any ideas?