Misfire or something else??

[Fordgirl01]

I have an 04 Navigator I’ve had for about 6 months. It has started acting up the past few weeks. At first I thought it was transmission related as it showed up driving in a hilly area one day. It acted like it didn’t know what gear it wanted to be in-several times it crawled up a hill until it finally decided to downshift. It didn’t really seem to slip, although it always feels funny to me how sneakily and smoothly it shifts normally. It would at times downshift only to shift back up seconds later. It was very hit and miss. Sometimes it would act totally fine, the next hill it acted like it was not going to make it.

So since that day, it seems more like a misfire, but it hadn’t thrown any codes. It was randomly spitting and sputtering with any load against it, but not always. It would also seem like the engine cuts out for a split second for no apparent reason. It does this sporadically just idling thought town or at cruising speed without a load against it. It hadn’t acted up consistently for any certain reason so it’s hard for me to describe what is going on.

It has been getting worse and today on my way home it finally seems like a misfire. I have dealt with a misfire 3 times (different vehicles but all Expys or Navis) and have never had one take this long to toss out a code. Usually they act up and within a day or two the CEL comes on.

So today as I was pulling a pretty good hill coing home from work, it was shuddering and skipping, it finally downshifted (I heard a pop that I also felt with my left foot-seems to have originated from that area under the vehicle) and the CEL came on flashing (my other misfires caused the light to come on but it did not immediately flash). I had my scanner with me so I pulled over and plugged it in (misfire cylinder 8 “pending”). I looked at the dash and the engine light was off. I limped it home (probably 10-15 miles) and the CEL never came back on. It still ran like it had a misfire though.

The MPG has not decreased like my other misfire episodes. It also still does the cutting out thing for a split second which I have never experienced before.

Also-maybe related, maybe not......lately I often have to hit the shifter with the heel of my hand (it has a floor shifter) or the ignition won’t work. Another new oddity....when I put it in drive to leave work today, it flat out quit-no stall like it was starved for fuel, just totally quit. I slipped it in neutral and it started back up and did not quit again.

Could this be some electrical issue related to the floor shift? Will a true misfire allow the CEL to go from flashing to off?

Where do I start?! I know the obvious is the plug and coil on #8 (of course it couldn’t be #5 or #4). I was just hoping maybe this is some sort of common sensor issue on the shifter or something simpler than that plug and coil that someone has encountered (hey, a gal can wish-right)!




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[Sgt Darkness]

Wow..... it’s probably #8 but that needs to be checked first. You may not have one but I have an old timing light I use to verify a miss on the plugs, plug wires or coils. The timing light won’t tell you which of the three it is but nowadays people replace the coil and plug at the same time. Have you done that lately? If you have to bump the shifter that to me indicates something is not quite right. I would check the plug-in below the shifter that sends info to the trans also, if in fact the Nav has the plug. While you’re there also check for tightness and condition of the wiring from the shifter. These things I do know and am sure someone else who has more knowledge will chime in soon. Let us know what you find....

 

[Fordgirl01]

Thank you. I don’t have a timing light but I’d probably just replace coil and plug after going to all the trouble to get at it. I’ve only had it less than a year so I have never replaced coils or plugs. It appears to have been well taken care of, so maybe they have been replaced before.

I will check the things you mentioned around the shifter this weekend.

Thanks again and I’ll keep you posted.


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[TobyU]

Just order a set of coils on ebay. I did a few months ago. Like 36.00.
Put new plugs and coils in it. Gap the plugs at .052.
It will probably run smooth as glass then.
Keep the old coils for backup/test coils. With exception of the ones you suspect like 8 etc.

A lot harder than Town Car but not too terrible.

Take the metal covers off and pull power steering reservoir bolts off and let it hang forward.

Use 3/8 drive ratchet and two short 3 inch and one 6 and one 12 or longer extensions the adjust for each plug.
Blow each plug well out with compressor blow gun before taking plug out. WATCH OUT for moisture that will blow out and get in your eyes.

Grease the inside of new boots that come with coils (have to pop them off and re-install them) with dielectric grease.

Use a plug socket that will hold the plug and not drop it but not stick so hard you can't get it out of the well.

I did my first set on 03 Navi in about 55 minutes.

 

[Fordgirl01]

TobyU-thank you for all of this info in one handy post!! I’ve changed a coil and plug before but never had to deal with one of the ones in the back.

I do have the fancy plug socket and even the Lisle tool for broken plugs (luckily haven’t had to use it yet).

I’ll get the set of coils you mentioned from eBay and change the rest while I’m at it.

Thanks again!


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[Fordgirl01]

Are any of the eBay kits better than others? I usually buy motorcraft or other known brands with a good reputation. I’ve heard off brand coils can be crap-what so you think?

I was looking at this post because of the MC plugs.




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[TobyU]

Are any of the eBay kits better than others? I usually buy motorcraft or other known brands with a good reputation. I’ve heard off brand coils can be crap-what so you think?

I was looking at this post because of the MC plugs.




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It's just a crap shoot either way you go. I saw those sets too and if you do the math they're slightly overpriced. They're just using the Motorcraft plugs to make you think you're getting a Motorcraft coils. I can buy the plugs locally for something like 249 or 299 a piece and O'Reilly Auto Parts so check around and do the math. You can even get different color coils if you look around but you're not going to be able to see these anyways. I actually like putting the red and the other ones on my Town Cars as opposed to the black ones. Lots of aftermarket to the parts stores are gray.
There are lots of sellers that show cutaway cross-sections and talk about 100% copper coils and stuff like that but you never really know. I have had great luck with all of them and I've use four or five different sets of the ones I've eBay.
Most have at least a one year warranty. If you search you can find longer or lifetime even but will the seller still be there or will you be able to contact them when you have a problem? Probably not. Locally these calls are about 40 bucks a piece with a lifetime warranty but it's not worth that much of a price increase. I can get them 4 $5 a piece or less and at that price I'll just throw one in the glove box and I always have tools with me so if I'm ever on a trip I can switch one out. And they're not that hard to do especially since most of my vehicles are Town Cars and they're even easier.
I have to ever have the set start going out in less than a couple of years I will look for a higher-quality call but so far the earliest I've ever had one fail was around eight years. That was on a V10. I ended up having two fail within the 8 to 9 and 1/2 year period.
I buy older higher mileage vehicles so almost everything I buy has a cool or two replaced with a different brand anyways. I just go through and put a fresh set of them and plugs and keep all the old ones for backups and test purposes.
When most people think they need a tune-up they really don't even need coils. Normally they should just put some new plugs in and replace all the rubber boots on their coils. Then if you later have a misfire you can check with the scan tool you might have to do a coil. Different ways of going about it I guess.

 

[Fordgirl01]

All of my vehicles are old too. I can’t see wasting money on a newer one just to have it rust. Also-its a good way to own a luxury vehicle on the cheap!

I was thinking the coil/plug set was cheap-like you said-buying just one coil locally is at least $40. The same plugs with the kit are $3.69 each at advance auto. I did order a kit like the one I sent the pic of. I’m sure it will work just fine. I have 3 old navigators so the spare coils I remove will not go to waste.

Thanks again for your advice and info. The coils will be here Saturday. I’m going to get started on Friday and at least try and get #8 out of there.


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[Fordgirl01]

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Ok-I’m out in my garage under the hood of this fancy misfiring Navigator! I snaked the cover off of the plugs/coils (my 99 doesn’t have a cover so they’re easier to get at)!

Can I somehow move this big braided covered whatever it is? It’s sitting right on top of the coil which made getting the cover off a challenge. The locking tab appears to be broken off the coil plug in too. I’m guessing I should put a new tab on it?

 

[Fordgirl01]

Got it-i wiggled it out but it looks like it will be a real challenge to get at the plug in that spot.

The rubber boot on coil #8 looks misshapen-like it’s squished together compared to the others.

I see the cover must hold them down. There are small bolts that hold them down in my 99.




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