Sounds like a lot of us have this problem.

1997 Expedition. 192,954 miles. 5.4 liter [330 cu in]
Vin: 1FMFU18L2VLA58115

AutoZone diagnostic check this morning says:

Definition: Cylinder Misfire detected-Cylinder #3 [third one back passenger side; can almost see that one.]

Explanation: The powertrain control module monitors the crankshaft speed and has detected a misfire condition.

Probable cause: Ignition coil fault-Spark plug[s], Ignition wires, Coil, Vacuum leak, Injector fault, High or Low fuel pressure.

Particulars: 5.4 liter, H.D. cooling, [get her home in event of coolant loss] trailer tow package, ect...R&R'ed spark plugs at around 130,000 with Bosch Platinum 4 prong plugs, all original with exception of water pump and alternator, rear bearings in the pumpkin, and front end rebuild. Normal stuff like brakes pads and rotors as they wear out. No big deal.


Of course 'Check Engine' light is on and once in a while is blinking for a few years now.
Everytime I check the engine, it's still right where I saw it last.


There are some U-Tube videos on how to check coil over plugs and fuel injectors.

Only funny thing sometimes it runs like a raped ape when stone cold. Is this because the mixture is a tad richer when cold? Or because the O2 sensors are waiting to come on line and lean things out? Or...


I have heard that if two COP's go bad better to replace all eight. Are the cheaper aftermarkets ones [8 for $150 on line good enough for a while?] Or do we need to stick to the outrageous Ford approved ones?


I'd like to thank any and all who might toss in there hat here.


skip.

 

Hi Skip, and welcome to the site.
You probably didn't look for or notice any white burn-through spots on the spark plug boots from the coils, but first , if you depend on the vehicle, then go the extra mile and use Ford coils and boots TOO ! Take your vin into the parts dept and get the right parts the first time. I'm a little concerned that you were driving the vehicle with the CE light flashing. It is flashing to alert you to a serious problem that could destroy your converter. Newer Fords will kill the injector so fuel will not get injected into the cyl and go to the converter to overheat and destroy it. I am not positive if that feature was present in the 97 models. There is always the possibility of a spark jumping to the engine instead of to the plug and creating a voltage spike that can take out the PCM. Believe me, the replacement of the remaining coils is a heck of a lot cheaper than a PCM.

 

Hanky, you are a smart man. I have not climbed down into the engine compartment to look~see for white spots, or other signs of sparks going to places they are not to go to. I can hear no arcing or spark snapping.

Having said that what is a PCM? But it's probably the engine control mod or some darn thing like that.

The cats on this 1997 are original [1997 is the first year they built these Expeditions.]

Ford only approved parts makes sense for COP's .Looks as if I'm going to have to bite the bullet and shell out some cash. I'm not complaining, this truck has not cost me very much in repairs and boy it is reliable.

One funny thing is the blower switch remains hot when I pull the key and the blowers, front and rear, stay on when things under the bonnet get wet.
So I have to remember to turn the switch to off to save the starting battery.
No big deal.

And of course the body is rusting away. Mechanically the under pinnings and all that stuff that makes it go, stop, turn, absorb bumps, and give a good quiet ride are still working well.

I will check that U-tube video on testing COP's and then...we'll see.

Thanx skip. Sturgeon Bay, WI where we are under a blizzard today and tomorrow.

 

Thank you for your kind words.
PCM stands for "powertrain control module" which is the vehicle's computer.
We can't always hear the spark jumping over the other sounds the engine makes.
Someday when the weather is more permitting it might be interesting to take a spray bottle with water and spray small areas one at a time to determine just where the cause for the blowers staying on resides. Might be just enough electrical leakage to hold the blower relay energized. Does anything else stay available to work like the signal lights or wipers after the ign is turned off? Some of the "body"functions are controlled by a body control module that Ford calls a GEM , generic electronic module".
Let' hope Mother Nature isn't too rough on you with the blizzard. Stay warm and have a Merry Christmas with a healthy and prosperous New Year !

 

All the electrics work on this early Exedition. Lites, warnings, door ajar, anti-lock brakes, air bags, jewel lamps, gages, radio [except no am reception] ect. All works. Oh every few months the light for the capacitor for the air bags winks on for a few minutes.
Never has seen anything plugged or bolted to the body that would monitor body chassis/movement. GEM. No air suspension.

Additionally I have a 1930 Ford Model 'A' 40-B [standard not Deluxe] Roadster. All 5,300 pieces have been R&R by me. She is an everyday runner in the summer. Had it since 1980. The 'Vin' # is the engine number which equates to 12-February-1929. Not surprising since O'Henry usually kept most of his inventory rolling around the country on railroad train cars. It was assembled in Atlanta, Georgia. Dates of assembly were kept numerically by the month and year. Based on cars made per day and per a specific week, this guy was built, best guess, on March 17, 1930. This was the year of BIG decline for the Model 'A'. It's the depression which was never more than a true 10%. Unlike today's made up 11%+ which is really about 15.6%+.

The wife bought a new 2007 Mercury Montego Premier AWD
Vin: 1MEHM43187G600834.
Has almost 16,000 miles on it as of 20-December-2012. The only thing worn out on it is the oil pan drain bolt as the computer dictates. No actually Ford R&R'ed the rear rotors and pads. Something was amiss there early on. Did not pay any attention to that and not pay for it either...maybe down the road again? Tires are rotated ever oil change by Ford. As long as I buy oil chanes at Ford, Witt Ford will replace the 17 inch Perelli P-6 tires, balance and valve stems for free. I have it in writing!!
The pisser is these ties loose pressure, think right through the aluminum rims. Porosity ?

Thanx. Merry Christmas. skip.

 

Stone cold zero degrees, even with bad C.O.P.'s the engine runs perfect till just when the temperature gage starts to show some heat. Then of course the engine lite flashes, the misfire starts, it shakes a wee bit, and it's always better if we motoring along with nearly no load. No load, less spark needed.

Does any of this good running when frozen happen because of a cold start/enrichment valve, or Ox sensor inoperative and waiting to come on line after the engine gets warm?

I can't take care of this till summer when I'll have two days for disassembly in warm weather.

skip.