I changed the plugs today in a 2004 trailblazer and the back plug was wet, had oil on it. i changed plugs because i was getting an engine light reading that said misfire.

Wet plug anything to worry about or is this normal?

 

It is very common for the spark plug tubes to leak on the 4200 i6 engine used in the GMT360/370 trucks. Most of the time this is solved by changing out the cam cover gasket and o-rings. That is assuming that the oil was on the top of the plug, external to the combustion chamber. Often, when this occurs, it will cause the rubber on the plug boot at the bottom of the coil to swell and allow the spark to leak out, causing a misfire.