No, diesel engines don't have ignition coil as they work on compression ignition and not on spark ignition as in diesel engines. Glow plugs used in diesel are like small electric heaters which use the mechanism of heating due to resistance during electrification.
Erythromycin. Erythromycin is a very common antibiotic treatment for walking pneumonia. It is very similar to penicillin when it comes to how it works, metabolizing bacteria-fighting 14-membered lactone rings in the liver. As a treatment for walking pneumonia, Erythromycin is prescribed through tablets, gels or injections.
I believe pneumonia generally shows up on x-rays, so I'd wait until Monday & see what the docs have to say. Staying away from alcohol, resting, eating properly & lots of fluids is still a good idea to help you recover. Viruses can last a long time & there aren't many effective treatments for them.