Spark plugs are fairly new changed them recently. Last month i changed all ignition coils due to engine misfiring but haven't touched the plugs. Were the plugs damaged by the misfires?

 

Why not? Just change them & start fresh. You would be second guessing yourself for as long as you have those unchanged plugs in. Every time you hear a noise or you think something is not right you will be worried its the plugs you left in after the misfiring. The price for the new plugs is well worth your mental well being. Mental in that you honsetly believe your car runs better after it is washed even though it doesent you believe it does.

 

not necessary but if coils were bad, in most cases, there may have been damage to the plugs. Either soaked plugs or something...I say change them with some coppers. Cheap, better conductor and will make u feel better knowing u got new plugs and coils instead of second guessing like Kevon1 said.