Anyone know cars?

I do need to get my suspension fixed, my new car still fishtailing over bumps. New shocks put on and it helped but it came back. One mechanic did diagnose it as needed new coil springs. That they are loose. But my own mechanic said you can't tell if springs are loose on a lift, as they hang down. I checked online and it says you are able to tell if loose on a lift...he's hesitant to do the spring because it "might" not fix it.
But I think it's worth a try. Any thoughts..are you able to tell loose springs on a lift?