Okay, so I was experiencing a misfire under acceleration, so I bought the Global Automotive coils (set of 8) off of Ebay. I started changing them out today and found coolant in/around nearly all of the old COPs. Not in the cylinder, but between the spark plugs/COPs and the gaps in the head where they sit. What does this indicate? I'm not all that familiar with the 5.4 motors so any help would be appreciated.

 

typically around the number 4 cylinder would indicate a heater hose leak but in all the cylinders? That is pretty uncommon. Are you sure it is in all of the plug wells?

 

Not ALL of them, but about 3 of the 5 that I have changed so far. The first one I changed (passenger side, very front of engine) I thought may have been due to a heater hose tee that I installed as part of a flush kit a while back, but it hasn't been leaking. I'm thinking maybe intake gasket?

This isn't the first time I've had corrosion/water in plug wells either. I bought the truck with a slight misfire, took it to a quick lube and paid $400 to have the water cleaned out of the cylinders. Ripoff, I know, but it was finals week and I didn't have time to DIY it. Few months later, after replacing two COPs and all the plugs, it started misfiring again. Took it to the dealer that time, and everything was corroded. They cleaned it up and replaced the plugs/COP boots. I'm about to my wits end with this stuff.

 

could be you have a bad intake there made of plastic and the early ones like yours have been failing. Theres only a couple of ways coolent can get in the plug holes. Bad heater hose or intake/gaskets.

 

Yea, like jethat said. Especially if it is on the passenger side only, it could be a heater hose or cracked intake manifold passenger side near the front aluminum coolant crossover where it mates to the composite.

 

It was a leaking intake gasket...pulled the intake off today, and sure enough the PO did a ****ty job with the RTV gasket maker. Didn't see any cracks in the manifold, but went ahead and ordered the Dorman one from Summit as well as all new Motorcraft plugs.

Hopefully this will also explain why my 5.4 has been gutless since I've owned it...I've got E-fans and exhaust and the truck still dragged ***.

 

Get some new gaskets.
You do not use RTV when putting on the intake-manifold.