I just got in my 96 miata 1.8 and it would not start. It has been sitting for 3 days. So first I checked the oil, barely a half quart low, so i added half quart. atill no start. I went to pull out a spark plug, pulled it, and it was drenced in oil. even the bottom half of my socket was drenched. I was thinking that maybe the valve cover could cause that????? I know it has some seepage on the outside but could that cause this problem???? Any ideas anyone?? Thanks a bunch....
Car has run fine until this

 

Sounds like some oil has spilt into the plug recess(s) and contaminated the HT leads, you may get away with cleaning and drying out, or if more than one lead is oiled up would be better fitting complete set of new leads.