I have read exhaustively on previous posts on this topic but wanted to run this by you guys for an opinion. Misfires in cyl 1&2. Swap coils on 1&5, clear codes, no change, same codes. Swap coils back. Then swap 2&5, clear codes and re-check, now only code for cyl 1.

Plugs were replaced with Motorcraft ones about 35k ago, dealer did it. Current mileage is 152,000. No coils or injectors have ever been replaced. I made a little attempt to remove cyl 1 plug to look at it but that sum bitch is tight, I didn't want to break it and then defeat my ability to replace an injector or coil on that cylinder and re-test. I live in Arizona, super dry here and no water has been on that engine in years. Coil boots were clean and dry.

Assume plug is good, which is my likely failed part, injector or coil? Obviously the injector replacement is a little more labor intensive than the coil.

Furthermore, I wonder why my cyl 2 misfire code went away?

Thank you guys for reading through another one of these posts, I appreciate it.

 

You can't assume that.

 

I understand that but I,m looking at like this, plugs have much less miles than OE injector and coil, reasonable deducing I guess. I've ordered a coi, injector and plug. I guess I'll see what happens. Thanks for the help.

 

Here's an update, I still need help. Replaced coil with a new Motorcraft, problem still there. Did the little screwdriver listening test to the injector, can clearly hear it firing. Ohm tested the injector, matches 2 others I tested-15.9 or so, within specs. Pulled plug, came out nicely thankfully, looks fine, put new plug in anyhow, cleared code and fired it up, still running rough and P0301 code.

Any advice for my next step(s) would be appreciated. Thanks guys.

 

I wish someone would of replied because I have having the exact same issue w/ plug #1 p-301 misfire. I'm on a 2nd new coil and new plug.

 

Have you ever changed your front O2 sensors? When they start going bad they can throw misfire codes and make the motor run like s***.