check engine lite came on, had a scan done and code said mis-fire cyl.3,,could this be a faulty coil and plug,it has a slight miss , nothing serious

 

Get the coil checked sooner rather than later, and yes that is a likely culprit.

 

Not on my Mazda but on my Mercury Villager with a Nissan engine, I was getting a random cylinder misfire code... After some playing around with plugs and wires, cap and rotor, etc. we narrowed it down to being cylinder 1 that was acting up. Since everything seemed to be working appropriately and there was plenty of spark, we figured it might be a clogged/bad injector. I ran a bunch of cleaner thru the system several times and the code and rough running/missing went away... Incidentally, it stopped acting up the exact morning that I finally gave up and had an appointment at the dealer for a look-see and service...

I'm still crossing my fingers that it was the injector and whatever was clogging it passed, but so far it has been at least 3 weeks and still running just fine.

So... you might want to consider your fuel system in your overall assessment of the situation too once you have eliminated a bad plug or coil...

 

Maybe so, but it isn't a random misfire code, it is a cylider 3 misfire code, and the coil problem is a known issue on our car.