Dodge: engine codes, dodge ram 1500, manifold vacuum

Question
hey i keep getting a cylinder misfire on number 7 po307 i changed the wire and plugs cap and rotor 1999 dodge ram 1500 5.2L y motor. i'm wondering if the fuel injector is bad?

Answer
HEY ED,HAVE YOU RUN A COMPRESSION CHECK ON CYLINDER 7 YET? DOES THIS ENGINE RUN ROUGH ENOUGH TO KNOW ITS MISFIRING? WHAT DID THE PLUG LOOK LIKE WHEN YOU REPLACED IT? DO YOU HAVE A VACUUM GAGE TO MEASURE INTAKE MANIFOLD VACUUM? SORRY ABOUT ALL THE QUESTIONS BUT I NEED JUST A BIT MORE SO I CAN BE MORE OF A HELP.TALK TO YA SOON,TIM. P.S. WHEN YOU CLEAR OUT THE CODE,HOW LONG BEFORE THE LIGHT COMES BACK ON?