Yes ,just like the other side fired when unplugged ,bad coils ...possible ground or under voltage or over voltage ,bad connection ...etc.
These are some or the harder things to track down ....just eleiminate the possibilities one at a time ,try the grounds and the power wires first to see if they are actually bad or its just a wire problem,then goto some new coils ,that way if it is a wire that caused it ,it will not happen again or it maybe just a wire issue....?
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Also the MSD site has some good info for trouble shooting.