#6 spark plug died with little warning

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OVERKILL

OVERKILL

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Was driving the truck yesterday, it was very low on fuel and acted a little funny, but I figured it was whatever was on the bottom of the tank. Filled it up at Esso, drove it home, ran fine. Fired it up this morning and it was missing like crazy. Felt like ZERO fire on one cylinder. It was freezing rain and I had to drive my son to school. FUN! Drove him to school, it ran the same (awful) the whole way there and back with no change. Parked it at home, my wife went out with her friend for a bit, it was snowing like crazy at this point. When she got back, I took it up to Ford, figured I had a coil go......... NOPE! #6 spark plug decided it didn't want to work anymore. crzy
 
A bizarre failure to be sure. Can't recall any plug failures in many many years, just doesn't happen much. What did they say happened?
 
Did the plug foul? Like old snowmobile plug fouling? Maybe that injector is running rich? I would bet some money that the plug they put in quits relatively soon too, but maybe it was just a bad plug. Can they test a coil out of the engine?
 
Originally Posted By: SteveSRT8
A bizarre failure to be sure. Can't recall any plug failures in many many years, just doesn't happen much. What did they say happened?
He said it was dead, and was wondering how many miles were on them. When I told him, he was very surprised.
 
Originally Posted By: IndyIan
Did the plug foul? Like old snowmobile plug fouling? Maybe that injector is running rich? I would bet some money that the plug they put in quits relatively soon too, but maybe it was just a bad plug. Can they test a coil out of the engine?
No, plug looked fine crzy other than a little less white than it should be, since it wasn't firing at all today.
 
Originally Posted By: SteveSRT8
if you drove around on it it was washed by fuel so the visual won't tell as much. I'd love to figure this one out.
I probably put 3Km on it with it misfiring? But yeah, it would have been cleaned somewhat I'm sure by the fuel wash, but really, it looked perfectly "normal" for a plug with its mileage, aside from not looking "dry" like they normally do. The mechanic at Ford thought it was really weird! And they were OEM Motorcraft plugs.
 
You could check the plug's resistance between the center electrode and the terminal. I bet it has an internal open.
 
Originally Posted By: mechtech2
Plugs wear for sure , but I can't recall an installed one breaking. Time will tell if this is the whole story with your car...
I originally thought it was the coil (they are known for coils) but swapping the coil from another cylinder didn't bring it back to life. It seems to be running just fine now. Also, there was no physical damage of any sort to the plug that came out. I think mechanicx is right, that it had some sort of internal issue.
 
I can't believe you drove it around like that. If i fired up my car in the AM and it wasn't running right, i'd instantly turn it off. If i can't diagnose the problem right away because of weather or work, i'd leave it for later. I won't have driven it like that. Could have cause damage and excess wear to that cylinder, piston, crankshaft, you name it. Not to mention if it was dumping fuel into the combustion chamber the entire time duh
 
Originally Posted By: Artem
I can't believe you drove it around like that. If i fired up my car in the AM and it wasn't running right, i'd instantly turn it off. If i can't diagnose the problem right away because of weather or work, i'd leave it for later. I won't have driven it like that. Could have cause damage and excess wear to that cylinder, piston, crankshaft, you name it. Not to mention if it was dumping fuel into the combustion chamber the entire time duh
Let's get something clear: I have a wife and three kids. The Expedition is paid for, and has 240,000Km on it. My kids need to go to school, and I'm sure as heck not dragging the M5 out of hibernation to run around on freakin' R-compounds in 4" of snow because the Expedition has a bloody misfire! There was no "diagnosis". It had a miss. It needed a coil or a plug. A modular engine is not so fragile that I'm going to damage it by driving it with a miss up to the dealership. I also drove it up to Ford when it launched #4 spark plug. It is a truck with an engine belonging to probably the longest lasting gasoline engine family in history. I think it can handle a misfire for a couple of Km's. You need a reality check dude.
 
Originally Posted By: OVERK1LL
Originally Posted By: Artem
I can't believe you drove it around like that. If i fired up my car in the AM and it wasn't running right, i'd instantly turn it off. If i can't diagnose the problem right away because of weather or work, i'd leave it for later. I won't have driven it like that. Could have cause damage and excess wear to that cylinder, piston, crankshaft, you name it. Not to mention if it was dumping fuel into the combustion chamber the entire time duh
Let's get something clear: I have a wife and three kids. The Expedition is paid for, and has 240,000Km on it. My kids need to go to school, and I'm sure as heck not dragging the M5 out of hibernation to run around on freakin' R-compounds in 4" of snow because the Expedition has a bloody misfire! There was no "diagnosis". It had a miss. It needed a coil or a plug. A modular engine is not so fragile that I'm going to damage it by driving it with a miss up to the dealership. I also drove it up to Ford when it launched #4 spark plug. It is a truck with an engine belonging to probably the longest lasting gasoline engine family in history. I think it can handle a misfire for a couple of Km's. You need a reality check dude.
+1 all around. When we had our expedition, and we had a coil pack get iffy, we drove it for 2 weeks until dad was working a schedule where he had time to replace it.
 
Originally Posted By: Artem
I can't believe you drove it around like that. If i fired up my car in the AM and it wasn't running right, i'd instantly turn it off. If i can't diagnose the problem right away because of weather or work, i'd leave it for later. I won't have driven it like that. Could have cause damage and excess wear to that cylinder, piston, crankshaft, you name it. Not to mention if it was dumping fuel into the combustion chamber the entire time duh
Yeah, because the 5.4 is a fragile flower that's just going to eat itself from a misfire. smirk
 
Yeah, not likely. Man, Artem, your head would spin if we told you some of our stories! I once drove a dodge van all the way from orlando to tampa with one intake stuck open due to a broken rocker arm. Backfired every single time it came around to that cylinder. Cost about 5 bucks for a pushrod and a rocker arm back then. Cheap fix.
 
That's a really odd failure. When they are cranking out millions of spark plugs there are bound to be a few duds though. I would have driven it too. People have done worse things to 5.4s.
 
Originally Posted By: Artem
I can't believe you drove it around like that. If i fired up my car in the AM and it wasn't running right, i'd instantly turn it off. If i can't diagnose the problem right away because of weather or work, i'd leave it for later. I won't have driven it like that. Could have cause damage and excess wear to that cylinder, piston, crankshaft, you name it. Not to mention if it was dumping fuel into the combustion chamber the entire time duh
Todays cars are smarter than that. Once it knows that cylinder isn't working it cuts the fuel off to prevent flooding the cyl with fuel and damaging the cats. All he did was drive across town with 1 piston pumping air.
 
My dad drove across town in a 2005 Ford Freestar with a bad coil pack so it was misfiring on one of the rear, hard to get at spark plugs. He said when he got to the parts store, the cat comverter was glowing hot. He got rid of the van a while later.
 
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