Cylinder 8 misfire....HELP!!!
Hi guys, I'm new to this forum and have found excellent information and expertise here. My problem is this; My 2005 F150 just turned over 200k and started throwing codes and idiling BADLY. Took it in to a local mechanic who changed the plugs, boots, and MAF sensor. Picked it up and still had the same codes thrown and bad idle. Mechanic flushed the fuel system, no luck. Third time in he replaced the #1 and #8 Ignition coils. Ran good for an hour and started the same thing. Took it in to Auto Zone and they said it read a misfire on the #8 cylinder..which just had the coil replaced. I can do most work on this truck myself but lack in diagnosing. Please help me with any suggestions. Should I replace the remaining 6 COP's? Would that have any affect on whats going on with the #8 misfire?