how can I tell which one is bad/5.4 liter v-8/year model 2000

 

You will need to be careful with the injector plugs when removing and reinstalling them. They can be easily damaged.
If you were to remove each individual coil plug the injector for each cylinder you unplug will keep injecting and cause problems with the converter(s), so we don't usually do that. Also , if there is a definite full time misfire that was caused by an electrical problem , the PCM will disable the injector to prevent a converter failure.
If you remove the injector plugs one at a time, watch for the one that shows no difference in engine rpm or doesn't change the intermittent misfire problem. That will help to at least pin down which cylinder has the problem. Once you do that you can remove the coil and look for white marks on the boot. If spark is jumping from the inside of the boot to ground you should see the white/grey mark on the boot.
If you don't see anything obvious you might try replacing that coil and see what happens.
Of course you can always try replacing one coil at a time until the misfire is gone providing that is why you asked your question.

 

My plugs/coil over plug/fuel injectors or electrical PCM have been miss firing the big V-8 on my 1997 [first year Expedition] for years. Were rolling up on 300,000 miles.


The 'Check Engine' light is on steady [every time I check, the engine is still there] or it's flashing at me and she just keeps on starting faster then I can let go of the key.


It miss's all the time. At idle. Worst under load. And smooth going down hill off the steep bridges when the engine is loafing. Still pulls a 3,000 lb load. Of course the fuel consumption sucks. But it's still cheaper than a payment. The Ford dealer put some Bosch 4 prong plugs in her at 153,000.


This Expedition is amazing! Still has the original exhaust, coolant, hoses, belt, water and fuel pump, all electrics still work with the exception of the heated back window. The all wheel/four wheel selector switch and down under stuff work fine. It has a trailer tow package and a 'get home cooling package' in case the coolant is lost.


I put on an alternator, replaced two rear window cast pot metal hinges, a pair of gas shocks to hold the window up. Two fuel filters, four sets of rotors, numerous pads, several sets of tires, rebuilt the front end suspension with new pieces and the bearings for the rear pumpkin.


All the fluids come out every year. Brake, P/S/, trans, front and rear end lubes. Change the engine oil and filter at around 8,000 to 10,000 miles. Just run Valvoline 5-30. All the rubber door seals are Vaseline rubbed.


The major problem is the sheet metal body is rusting away. Once it's gone, I'm thinking of welding up a one piece four door aluminum body much like Henry Ford's Model 'A' Woodies with a drop down tail gate. I'll just bolt it back down to the rubber donuts under the rusting body. It will be ugly. An intake manifold and carb would be nice going back to the 1960's technologies I understand and can fix.


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