Rainy week here in NJ.. Tuesday night 5.4 expy started missing while on Parkway... Got up next morning... same issue...

This thing was missing like the old days before electronic ignitions
..when you would hit a puddle with points and condensors and just about stall, this crap is back to the future!!

Went to local Autozone to get free readout.. they stated that if Check Engine Light isnt lit, they wont get a read on cop issue with their tester

So in frustration went back and bought STP Wire Dryer, sprayed all cops down thouroughly, let dry... problem solved right away, at least for now...

Guess the next time it happens, I may spray Cops 1 at a time, and figure out issue by process of emilimination

Anyone else have quick way to figure out where the bad COP is?

 

Nope, Unless the COP totally fails and that don't happen that often - if ever.

If you have access to the dealerships scanner and Mode 6 it - you get cylinder history reading. COP's fail under loads and a hot-spot is after the shift into OD in any givin drive cycle. Mode 6 reveals cylinder miscue, you can pinpoint the coil that's bad thru history readings your on-board stores in memory.

You can aquire software for your laptop that will spinal tap via peripheral/media.

Screw all that, I just go on ebay and buy the COPs kit that comes with plugs. For $130 you can replace everything and just be done with it.

 

Well I think I discovered the solution, quick, easy and cheap. about $4 bucks for the can!

As I mentioned in Novemeber, I sprayed all COPS with STP wire dryer, It solved the problem for about 2 months,

The next time it acted up, I sprayed just one side very liberally, let it dry, to identify which side had the bad coil It was the passenger side.

I then thought about it, and it seem that the coil on plugs dont nessasarily go bad, water finds it way into the spark plug opening, being trapped and arcing the spark, which is why the check engine light does not come on, the COP is GOOD, it is sending sprak to the plug , just shorting out on the way down to the plug.

There apparently is a pliable gasket at the bottom of the cop to prevent water getting down into the plug recess, when gasket is unlubed, water gets trapped and causes missfire. Thats why sometimes it may go away if you burn it off.

So I sprayed the STP Wire dryer liberally on top of the cops, and around the base. Let dry for an hour, It has entirely solved the problem. Now ok Since January!

I wonder how much Ford dealerships have profited from THIS design flaw when the cops were actually ok?

 

That can happen as you sugest and has , but the most common cause of COP failure is age and thermal break down, they weaken and misfire under load within the drivecycle - usually after the shift to OD as you begin to accelerate.

You should only use dielectric grease to shield from the elements and guide spark. If you don't use this grease in the boots - coil spark will burn carbon trails inside the boots and are visible under inspection.

You use two O-rings for the cambers , then seal the chambers with dielectric grease.

To test - you can run a probe thru the firewall , clamp on the side of any COP , then go for a ride then someone watching the hits

 

Purchase a new set of cop boots fron Autozone.Use the diaelectric grease
for the added protection as stated in previous post.
Short of that you can purchase Cops on e-bay for about $12.00 apiece.