99 Dodge Ram compression readings

I have a 99 dodge ram 1500 5.9 v8 136000 miles I reclenty did a compression check all cylinders came back with a 140 psi reading except one that has a 105 so now I am unsure of what to do, do I change the plugs and wires or what should I do. Is it still safe to drive like this, what could be the reprocussions for driving it as is. Any suggestions and/or ideas would be helpful thanks