I think I found the answer to my question at
https://rustyautos.com/can-i-drive-w...lty-coil-pack/
"It is possible to damage your engine so unless it’s an emergency, I wouldn’t put undue stress on the engine. Running the engine on a cylinder less will mean the car is underpowered and off-balance. Note also that most cars will register a faulty coil and immediately stop gas feed to that cylinder. However,
damage may be caused if the fault isn’t registered by the PCM and the dead cylinder continues to receive gas. Your catalytic converter and oxygen sensors may become contaminated by raw gas and need to be replaced. Raw gas will dilute the motor oil too and put major mechanical components at risk. Any misfire should be repaired ASAP."
That sounds pretty serious. I think I should pick up a coil pack in addition to spark plugs and see if I can get an earlier appointment. Thoughts?