New to this site, hoping to be able to figure some things out...I have an 03 F150 Supercrew, 5.4. it has been running a little rough latley, so i had check for codes, and got 2...P0172-system too rich bank 1, and P0304- cyl. 4 misfire. i have been told that told that cyl 4 goes out because the heater coil commonly drips on it??? Has anyone else had these issues? Thanks!

 

Welcome to the site. I've got an 02 with 113,xxx on it without any such problems.

 

Your intel is correct. Rich condition caused my misfire. Cylinder #4 is next to firewall on passenger side, under heater hoses. Leakage on the COP, causing failure, has been reported on several occasions. Further searching will provide a source for the COP. I would recommend just replacing all 8 of them as a set.

 

I just had the same problem, replaced all 8 of my cop's and plugs and it runs like a champ now.

 

Thank you to all who have replied! I had someone do a pressure test on the coolant system, because i have had to add coolent several times, recently, and testing revealed a leaking head gasket...ouch. thanks, again for all of the suggestions!