why will the pk3 system won't let the car start. on 1997 Buick Park Avenue

sometimes when I go to start my car the pk3 system locks me out and I have to let the car set until it decides to start.this could be a short time or up to an hour.once it starts it will be fine for a while but if I turn it off it will do the same thing when I try to start it right away.

Asked by for the 1997 Buick Park Avenue
Have no idea what you are calling the "pk3 system".
I believe you have a antitheft system problem. The most common problem is the ignition lock cylinder.