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?