I recently changed my plugs and the next day the engine started running rough and the check engine light came on with the trouble code P0305 (cylinder 5 missing).
In the last week I have changed the
PCV valve
Spark plugs (Motor Craft)
Fuel filter

It gets worse as the engine warms up and when accelerating.
It also idles smooth until it is put into gear.

2001 f150
4.6
162k
Never had any issues until now.


Any help will be appreciated.

 

Problem solved. Gave in and went to JustAnswer. The expert hit it on the head the first time. Changed the COP on #5 now she's purring like a kitten.