Another misfire thread going here...

1998 4.6L "W" VIN

Cylinder 4 misfire, its random, never misfires when motor is completely cold, but once it warms up, it is intermittent. Comes and goes at it wishes. I changed the plug, the wires are a couple years old. I wouldnt think its the coil, because if it was a coil, wouldnt it be all the time? I

A while back I had some fluid buildup in the spark plug well on #4, and I was wondering that if the antifreeze/water that was in there could have damaged the wire? My reasoning for this thought is if it split the wire, when the rubber on the casing gets hot, it would expand causing the wire to seperate?? Maybe I am wrong though, thats why I am asking for help.

Thanks for the help!

-MColford

 

Check fuel pressure, - rule that out first thing.

Check plug chambers/ blow them out.

Check the plug wires/resistance w/multi-meter set to "Ohms"/end to end. You gauge them Ohms per foot, so roughly maybe 5000 or 6000 per foot. So, if your testing a 3' wire and you get 18,000 Ohms, your @ 6,000 per foot. A comparison is the best way.

Check the connectors, clean them up if they look bad. Just common sense stuff.

Plugs, -you know what to do there, check for evidence of a problem - Motorcraft hopefully lol. Coolant leaks @ the firewall end up in #3/#4. Those leaks can and usually are intermittent. -Meaning, coolant may burst from the HC hose end/engine side when pressure conditions are met. Leaving no evidence other than what may be in the plug chamber itself.

Swap coils, one for the other. Mark #4 before hand, you'll be swapping #4 to the #1 spot and vice verso.

Yea, you can't really check a coil with that type of miss, but you can get around that if you have a DTC,- and also eliminate a few other possibilities.

 

had a couple coils go bad. one went totally out right away. another was off and on for a month or two. that was the first i had ever dealt and didnt know what the problem was. seems cold it would stutter and bog it but once warmed up would run fine. try swappin coils like mentioned but odds are its a coil

 

He only has two coils, not sure your aware. Yea, that engine, (4.6L) in 1998 used Coil Packs/ 4 cyl per pack. Same principle, but he can only swap #4 and #1 around to determine the #4 run to be bad or buggy. Here's what he has -



See what I mean, - the entire pack has to swapped.

 

did you ever fix the antifreeze in the plug hole problem, cause my heater core hose was leaking antifreeze down into the same plug hole, cause those hoses suck, and it eventually cracked the rubber on the long rubber tube going down into the hole, causing it to miss intermitantly, so yes i would change your spark plug wire for the #4 spark plug, and check those heater core hoses

 

Yes I fixed the anti-freeze issue.

So I swapped the plug out with a new one, still had a misfire, and today i swapped a wire from a buddy's F150, and it cleared up, so I took my wires back to Autozone, and they replaced them free of charge (Lifetime Warranty). Shes running good now!

A coolant flush in the morning, and Im ready for whatever life tosses at me for a while.

Thanks for the help!

 

Iiiittttsssss back. When the truck is dead cold (been sitting for a few hours) it will run perfect until warms up, then starts what feels like missing, but wont throw a CEL. I have replaced the plug, wires, and about to replace the coil, but dont want to unless I have to. But at the same time I cant get another idea until I get a CEL.

Any other possibilities? Im starting to get annoyed.

 

got ya on the coil pack. this is crazy cause my gf's mustang 2000 6 cylinder is also misfiring on #4 cylinder. changed plug and wire still nothin. gonna change coil tmrw hopefully. someone told me maybe a fuel injector problem?????? i have no idea at this point

 

Stay out of Autozone and put Motorcraft parts in it.

 

I told you what to do, - your not listening.

Your getting annoyed to ?

 

JBREW: Whats a DTC ?

 

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