Hello everyone,
About 6 months ago (1k miles) i did the intake gasket on my 2010 E-150 (4.6) because it leaked, causing misfiring and taking out my cat. Yesterday I got a misfire on cylinder 6 again, coolant in the spark plug gallery again. I checked spark plug 5 + 7 and they look good. I didn't see any coolant except all dried up on the coil pack/in the galley.. I'm guessing I have to do the job again but frankly I don't know what I can do different or really what is going on now. I would think that spark plug 5 would have coolant in it but it was clean. I don't get it and frankly I'm feeling pretty hopeless about this vehicle.

 

There is another way for coolant to get into the combustion chamber and that could include the head cracked, or head gasket for that cyl.

The way to verify what we suspect is with a leak down test where controlled air pressure is applied to the cyl, while on compression stroke,and check for noise coming out of radiator fill hole. This requires some special equip and might be a good idea to have qualified shop check this for you.