'01 dakota #4 misfire RED SPARK PLUGS????
 

check engine light came on. P0304 mechanic said it was #4 cylinder misfire. He changed the spark plugs. The plug tops were RED???
He'd never seen a red tip. the cel went off I took it home.
20 miles later the cel came on again. I checked the code-P0304 #4 cyl misfire.
What do I do next?
148,000 miles 6 cyl quad