engine light on

Recently replaced valve cover gaskets due to oil flooding spark plug wells, had replaced 3 coils prior, now have blinking "Service Engine Soon" light and engine is missing, assuming it is a faulty coil, is there anyway to determine which has failed.

my check engine light is on all the time. when i drive it for like 10 miles i get a transmission fault i dont know what is the problem if any suggestions please help. thank you