Just picked up a decemntly low milage 91 LS and had some questions regarding some play in the PRNDL. It's got about 1/2''-1'' of play to the left and right and when putting the car into gear, especially drive, the car jerks forward or backwards a pretty good amount. Wondering if anyones had the same issues or knows the route to getting this sorted.

 

Time to check all of your mounts. Set up a camera underneath the car, or have a buddy help you (don't run them over, of course).

Look at the transmission mount and differential bushings to start

 

The issue with the play in the transmission handle can be repaired by a mechanic that has to take the unit apart and replace bushings deep within. It is not a do it yourself job, I did not do mine, had it fixed cost me about $300. The issue you have with the noise from under the car with the jerking is in your driveshaft. I just had a driveshaft center support carrier bearing replaced in my 1992 and I paid my local guys $300. A nationwide company in town wanted $500. Don't be afraid to put some money into the car as these were the best cars ever made. Keeping them up is way better than new car payments!