Hello everyone! New here to this forum. I have an issue with my wife's 99 Navigator. It has the 5.4 DOHC. I know ford has an issue with moisture getting onto the coil for the #4 cyclinder on these motors. I didn't have a problem with missfires or the multiple cyclinder missfires that I am now getting until I was a moron and decided to clean some of the dirt off her motor and engine compartment. I should have left it alone Either way, I pulled the cover off the pass. side valve cover and guess what I saw? Moisture all over it and the #4 cyclinder plug. Is there a trick to get rid of this moisture and get this thing to run right again? Should I just leave the cover off and wait for the water to evaporate or blow it off with the air compressor?

I miss distributors, caps, rotors, and simple pushrod setups.

 

There is a coolant line for the heater core that is directly overhead of the #4 COP. The clamp has a history of coming loose and allowing coolant to drip onto the #4 COP. This usually leads to COP failure and a #4 misfire.

I'd check/tighten the coolant line clamp, then clean up the entire area with compressed air. Remove the COP, blow out the hole with compressed air and clean the area again.

Replace the plug (Motorcraft only is suggested) and the COP. using plenty of dielectric grease on the COP boot.

Reset the computer by disconnecting the battery for 15 minutes.

Steve

 

Is there a problem with replacing just the one COP or do I need to replace all 4 on that side?

 

Only replace the bad COP. No need to replace any others until they fail.

Steve

 

The cylinder 4 misfire is one thing, but the random cylinder misfire is another. Did you pressure wash the motor?

 

No I didn't pressure wash the motor. Just used a regular garden hose but I also flushed the anitfrieeze from the motor and radiator and refilled it. The top of the motor was exposed to quite a bit of water for some time. I've driven it more miles than I should have already with it running like this, so I want to repair some of the issues before I cause any further damage.

 

Even a garden hose can cause water to get down into the plug wells and wreak havoc with the function of the ignition system.

I'd pull all of the COPs out, dry the hole with comressed air, pull each plug and inspect each for carbon tracks (or just replace them), then reassemble useing a VERY generous amount of dielectric grease inside the COP boot. Buy the LARGE tube of grease and try to use a lot of it.

Steve

 

X 2

If you're going to pull it all apart, change the plugs. SLather that dielectric on them (to much won't hurt) and when you put it back together, all should be well. Be forewarned however, removing some of them are a real biatch.

 

I could already forsee some swearing and bleeding in my near future when I finally get around to replacing these. My wife is getting sick of driving the mountaineer with no AC and 3 young boys in the back seat.