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Misfire issue

96ExplorerXL4x4

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City, State
Bonney Lake, Washington
Year, Model & Trim Level
2003 Ford Expedition
Ok, is this a manual tranny thing or what?!

I replaced the plugs and wires less than a yuear ago and the truck is already misfiring AGAIN! I put in NAPA Belden Premium wires and Autolite plugs last January. Should I try a different brand of plugs? Is there something else I should replace? Thoughts!

Thanks!
-John
 



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Did you pull out the plugs and see what they look like? It shouldn't have anything to do with the fact that it's a manual transmission (unless you are driving it incorrectly). Also, how many miles are on the engine?
 






dynamite196 said:
Did you pull out the plugs and see what they look like? It shouldn't have anything to do with the fact that it's a manual transmission (unless you are driving it incorrectly). Also, how many miles are on the engine?

The last set I changed out didn't look abnormal, just OLD. I have not checked the set I am currently running. The engine has 116k miles.
 












wait till it's dark outside, pop the hood and start the engine and look for sparks or bright spots (flashes) under the hood.

you will need to remove the light bulb from under the hood if it's not already missing or blown.

if you see any flashes, where did they come from. if the spark plug wires get too hot they can short to the engine causing a miss and generating a flash, I had a mechanic friend who was a big jokester had me run my hand down the wires while the car was running in the daylight just to see me get shocked.

also jiggle the plug wires a little to simulate movement of the vehicle.

be careful and keep a flashlight handy, don't get into the belts.

David
 






wait till it's dark outside, pop the hood and start the engine and look for sparks or bright spots (flashes) under the hood.

you will need to remove the light bulb from under the hood if it's not already missing or blown.

if you see any flashes, where did they come from. if the spark plug wires get too hot they can short to the engine causing a miss and generating a flash, I had a mechanic friend who was a big jokester had me run my hand down the wires while the car was running in the daylight just to see me get shocked.

also jiggle the plug wires a little to simulate movement of the vehicle.

be careful and keep a flashlight handy, don't get into the belts.

David


David I stumbled on your reply. I had the samething with the wires. firing at the spark plugs, at the bottom of the boot and at random places in the wire. I replaced the wires and plugs. I still have the same problem as if they where not replaced. But I did regain power and 18mpg. But the big problem is that I can't pass emission, be cause they said there is a mis. All of the plugs are doing it. Also the wire is arcing at random spots on ground with good wire (no brakes in the wire). I did ohm the coil out. 5.5ohms everywhere you can check. The engine runs at full power without any drops in power. Idles at 700 rpms, smoothly. Any ideas.
 






David I stumbled on your reply. I had the samething with the wires. firing at the spark plugs, at the bottom of the boot and at random places in the wire. I replaced the wires and plugs. I still have the same problem as if they where not replaced. But I did regain power and 18mpg. But the big problem is that I can't pass emission, be cause they said there is a mis. All of the plugs are doing it. Also the wire is arcing at random spots on ground with good wire (no brakes in the wire). I did ohm the coil out. 5.5ohms everywhere you can check. The engine runs at full power without any drops in power. Idles at 700 rpms, smoothly. Any ideas.

Did you put dielectric grease on all the plug wire connections? Also, sometimes the boot can be pulled down further on the wire so it sits lower on the plug with relation to the acutal plug wire terminal inside the boot.
 






Every plug has the dielectric grease on it. Each boot plug is pushed all the way down in the plug. I read somewhere on EF, that the coil couldn't be strong enough to make full power though the plugs. That would make the extra spark find an easier way out of the wire. I'm use the Autolite Double Platum plugs.
 






Coolant leaking down?

If the coolant is leaking down and there is no sign of a leak on the outside, you might have a cracked head. The coolant leaking into the cylinder and cracking the insulation right at the tip at the + electrode.

Cracked heads are very common to the Cologne engines......disregard all this if you have a 5.0
 






No leaks. All of the boots are sparking at the bottom. The flashes are like greenish and they do became brighter as you rev. All new wires and plugs. Should I use better wires, like bosch wires. Now I have the duralast wires now. Autolite plugs.
 






Dumb question, but are the plug boots fully seated on the plugs? I know with mine because of the crappy angle you have to work with they feel like they are clicked down on the plug when they aren't yet. it really takes some wiggling to get them to engage on the plug and you should feel/hear a clicking sound.
 












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