I have a 2009 Ford Escape with 190000 miles, the vehicle was running fine then it spit out a P 0306 code for a number 6 cyl misfire. Then I found out that the owner had not changed the plugs for 90000 miles. After changing the plugs, the code reader still put out the same code. I then changed the coil, for # 6. Code is still there, is it possible that between the bad plugs and coil caused the ECM to go bad?

 

Hook up your OBD reader and clear the code, see if that helps.

 

^^^ and if plug wires are original replace.