PO305 code on a 2001

I have this error when the engine light comes on PO305?
Just wondring where to start to fix this problem .
Miss fire in the number 5 cyclinder is this correct?
thanks
Ryanjenna

Just a update I took it in to see what the problem was they told me it was a miss fire had to change the sparkplugs 90 dollars just for the plugs ....wow..
256 dollars after the charge to install them
deffenitly doing the sparkplugs next time.
Ryanjenna