jc1kz

I read somewhere in the fourms here, now I can not remember who had the same issue...just want to know what needs to be done.?
I have a '94 C280 w202 (inline six) My car was suffering from the low idle/would die at stops/like the coils were bad...took it to o'rielly's and got the code P0300 (random misfire) so I bought new spark plugs and a torque wrench, and set off to replace the plugs and coils....removed the plactic MAF air intake (the MAF was good and clean but past the MAF the plastic was smuggie/oily and there was a smaller ??? MAF ??? and it was dirty w/oil) There was a bit of oil going down the throtle body also. So removed the cover for the coils and spark plugs and all looks good, then I remove #1 & #2 plugs they were okay (but did need ro be replaced) then I went in to remove #3 and it had oil on the plug and I guess it dripped down into the cylinder.....cleaned what I could and replaced w/new plug, #4 was okay then #5 also had oil, I did the same cleaned and replaced w/new plugs....(didn't replace any coils) I just replaced the MAF and breather plastic and started the car.....A puff of blue smoke came off the engine area, and every thing worked fine no stalling, it idled just fine too....turned it off and replaced every thing back on the way it should go and started it again and took it for a spin.....(about five miles and back) as I parked it and left it to idled it acted fine....but now I wonder what that smaller (MAF ???) was and where did all that oil come from???? and what to do about that.....I didn't see any oil in the area around the coils and spark plugs untill I removed the #3 & #5 plugs....please advise/help

Thank You,
Steve