I recently pulled my 98 5.4 out for a spin and soon got a flashing check engine light. My OBDII read cylinder misfire. So after poking around under the hood I discoverd that the 7 cylinder was not firing properly. I pulled the coil pack out and immediately noticed it has what I think was coolant. I used an air blower and blew all of the remaining "water" out, put the pack back in and it solved the problem. My question is does anyone have any idea how water or coolant got in there. Also, I did replace the heater hose that is notorious for leaking into that area and I replaced the intake gasket apprx. one year ago. I let it run to operating temperature but cannot see any active leaks. Do you guys have any suggestions? Thank you in advance.

Matt

 

The heater hose you mentioned would be my first thought, but you said you replaced it. Is there a chance that you slurped some coolant in there when you did the heater hose? If you take a paper towel fold it and wrap it around the heater hose connection and secure it with some twist ties, you can drive it around for a few days then check it. When you take off the paper towel if it's stained or wet then that is probably the water source.

Also if you have a bad or missing weather strip on the hood by the cowl it can take on water in the rain or car wash.

Good luck

 

Just to update: I ran water with a garden hose onto my windsheild so that it would go into the gutter at the bottom of the glass. Within a minute it was dripping out of a small hole where a tabbed washer is placed in order to secure a ground strap(i think) from the intake to the cowling. This drip goes directly onto the heater hoses coming from the heater core and onto the coil packs. I believe this is where it came from. I am going to place a bit of silicon over the small hole and see if that stops it. I update my findings.

Matt

 

Try to find where the cowl drains and make sure that it or they are clear. By putting silicon where it is leaking now you may be creating a "lake" in there that could give you more issues down the road.

Glad you found the source of the leak.