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