Update the computer or change cops and plugs

[Jdcline54]

So I have a 2003 expedition 5.4l that has the intermittent problem while driving in high temps. (sometimes throws the cylinder misfire code) and I was reading the TSBs on ALLDATA...

It says specifically to NOT change the coils and plugs but rather to update the computer to a certain release... Im curious if anyone out there knows anything about this or has done it... did it correct the problem?

I am probably going to go ahead and change the cops and the plugs anyways as I am at about 180,000 miles. Im just curious to know if after doing so will it be safe to send my daughter over the mountain (about 100 miles) or if it will still be plagued with the same issue.

thanks in advance!

 

[1955moose]

Tough question to answer that it won't act up. We here at the forum only recommend changing out the Ford coils that are actually bad, and throwing a code on that cylinder. As far as spark plugs, yes change them, and again Ford ones seem to work the best overall. Can you post what codes you have, and what the Tsb says. This is the first I've heard in almost 4 years of being here, that a procedure that could correct a Miss fire of say p0301 code, which is cylinder #1. I'm sure one of the others would have mentioned this tech service bulletin before.

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[Jdcline54]

Tough question to answer that it won't act up. We here at the forum only recommend changing out the Ford coils that are actually bad, and throwing a code on that cylinder. As far as spark plugs, yes change them, and again Ford ones seem to work the best overall. Can you post what codes you have, and what the Tsb says. This is the first I've heard in almost 4 years of being here, that a procedure that could correct a Miss fire of say p0301 code, which is cylinder #1. I'm sure one of the others would have mentioned this tech service bulletin before.

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I don't remember which cylinder specifically was misfiring.. Either 1 or 3 but it was a p030x for sure

I will post a picture of the TSB. Hopefully you'll be able to see it.. Ive had issues on other forums posting pictures.

 

[Hamfisted]

Are you getting DTC codes ? Do you experience driveability issues ( like you feel it missing, or a lack of power ...) ?
That TSB computer update is done when you get codes but no driveability issues. If you are experiencing cylinder(s) missing and the associated codes then change the COP on that cylinder, and see if the codes and issues go away. If your sparkplugs are more than 50k miles old then change the sparkplugs as well. Use Motorcraft parts if possible. If you're sending your daughter over the mountains in a 15 year old Expy with unknown reliability issues make sure she has AAA .

 

[Jdcline54]

I do have drive ability issues. So now I must ask why only change the cop on the misfiring cylinder? Rather than changing them all at once?

 

[Hamfisted]

COP failures are random. They can last a month, or last forever. In fact many times it's the coil to plug boot, or moisture in the sparkplug hole that causes the misfire, but it's still registered as a misfire on that cylinder. A shop will tell you to replace them all because it's the same labor when doing a sparkplug change. It's just added expense for the owner. But by all means change them out if you want to. There's no harm in it and it'll give you peace of mind and a known history of the COP's and plugs. I have a pile of them in my parts bin, but I just change them out as needed. But it's my Expy, and me driving it, so I'm the only one that is inconvenienced if one pops bad. Really in 200k miles I've only changed out two.

 

[Jdcline54]

Good to know. Thanks for the info

 

[Plati]

My 03 5.4 had p0304 intermittent misfire, only when it sat for a while or first few miles of driving. My shop only replaced #4 cop & plug to fix. 180k miles ... They didn't see need to do all 8. Plugs were done at 100k, cops otherwise original. They advised good to fix misfire before they ruin cats. Cop was visually bad

 

[1955moose]

If your hell bent on changing all 8, spring for the Motorcraft ones, they don't burn out like the others. I'm with Mr sticker's mechanic, and replace the coil boots, the plugs and just the failing coils. Also it's been said before, but your new, have them fix any coolant leaks near the coils, if you have them.

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[Jdcline54]

If your hell bent on changing all 8, spring for the Motorcraft ones, they don't burn out like the others. I'm with Mr sticker's mechanic, and replace the coil boots, the plugs and just the failing coils. Also it's been said before, but your new, have them fix any coolant leaks near the coils, if you have them.

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yeah I'll be doing the work myself I've been putting it off for about 2 years but I'm done being concerned about it. I got Motorcraft coils and Autolite plugs. I've read just about everything there is to know on this subject but the update the computer thing was new to me so I thought I'd see if anybody had any experience on the subject or thoughts at least.

by any chance do you or anyone else know what resistance the coil should show if tested with a meter?

 

[Trainmaster]

I don't know the resistance but the problem with quality coils seldom lies with high resistance but with insulation leakage, which would be difficult to test.

Remember plug wires? You'd put on the cheap $6 wires, open the hood at night and it would look like Star Wars down there there with all the arcing. A bad coil often arcs to ground, builds carbon tracks and shorts on the secondary side instead of sparking the plug. You're not going to read that with a meter on the coil.

That's why it's important to change the boots. They can carbonize and permit the spark to short to the head.

The Chinese replacements are another story. They just go on fire or melt.

 

[1955moose]

Wasn't that cool though. Grab your buddy's and about 6 beers in you, and ooh ahh! Who cares it bucked like a rodeo bull! As far as resistance primary side is generally .8 to 1.5 thousand ohms, secondary 8-12 thousand. You can look up exact specs but that's safe for any coil, whether old style round tube or Cops. Coils are coils, they all do the same job, supplying spark to plug!

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[Habbibie]

I'm sorry OP I didn't read through the whole replies but does the misfire occured under hard acceleration or its truly just random regardless of throttle input? I been through both symptoms with my expedition but they both took me a while to figure out and I just want to direct you in the right direction on which of the two you're having!

 

[1955moose]

He doesn't say, but is concerned about his daughter driving over 100 miles. It's intermittent at higher temps.

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[Habbibie]

He doesn't say, but is concerned about his daughter driving over 100 miles. It's intermittent at higher temps.

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If its truly just random but only effected by higher temps then injection, electrical and the mechanical (NOT electrical) side of ignition is 100% out of the question (i.e. spark plugs & coils). main concern should be whatever it is that gets hot enough to fail is the number one suspect.... before on something like this I would use the expertise of Bob @Bedrck47 and @stamp11127 but Bob is gone and stamp is like a snowy day in Hawaii nowadays...

 

[stamp11127]

Bob and I had a little rivalry going on with who could answer the posts first. Every answer had to be 100% accurate or he would let me know about it. Since he has passed the desire is no longer there. May be time to sit in the shadows and let others have a go at it.

 

[1955moose]

He was a ball buster Bob was. He used to send me a pm whenever I screwed up. Always constructive though. Stamp no offense to the other top wrenches on our forum, but nobody comes forth like you do, with the knowledge for repairs. Especially in AC and electrical diagnosis. Nah, you gotta hang out, the partys just starting.

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[Jdcline54]

just to update, I went ahead and changed out all eight plugs and all eight cops over the weekend. all is well Expedition is running excellent, gas mileage has substantially gone up.

also I have to say this job isn't as painful as every post I've read makes it sound. They make it sound as if that number 4 plug (the back one on the right side) specifically is nearly impossible to get out. Although it was no picnic at the beach, I found it pretty easy with a 4 inch extension, a universal and a 10in extension. so for those people out there who have been avoiding doing this job for the fact that everything they read makes a sound so hard, I suggest just get in there and do it.
I had been putting this job off for over a year due to worries and concerns that I have read all over every page on the internet. And all I did was cause more damage to my plugs, and inevitably my engine.

thanks again to everybody that offered up some info for me. I just really like to understand what's going on before I jump into stuff.

 

[blue oval guy]

putting it off for 2 years?! The minute my old truck has anything wrong with it (engine related) i'm pulling it into my shop that same night. But that's just me..
good luck with your troubleshooting.

 

[1955moose]

Nothing in life is hard unless you don't understand, or haven't done it. I remember when I was I think around 11 or 12, and the pedal Crank on my sting ray bike broke. I was going to have a friend change it. I kept pumping him for info, on how he was going to do it, what kind of grease he was going to use. I said to myself, why pay this fool, I can do this job, and pocket the cash. I did it myself, and was so proud. Ridiculous easy, like most things in life. God I miss that sting ray bike, popped great wheelies!

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