I'm more familiar with them than I'd prefer. My regular car forums have thus far failed me. Hope me MRF-Kenobi, you're my only hope.

By "familiar," I mean, what would cause them to go bad repeatedly?

It's a 2004 Mazda MPV, and "bad coils" are a known-issue with second-gen MPVs, and according to my auto parts store counterman, many other Duratec V6s.

It had been misfiring very noticeably, if somewhat intermittently. Couldn't pin it down anything weather related. I replaced all 6 at 80K miles. Didn't get a CEL but 6 new coils and plugs got it running perfectly for another 20K miles.

And then I got the exact same symptoms again, but with a CEL this time: misfiring at #1. The back bank (cylinders 1-2-3) I replaced again, again with new plugs.

That got it running perfectly for 1 glorious week. Now I have a CEL for two of the three in back, #1 and #3. I want to set the vehicle aflame and call it a day.

Rather than go get another 3 free coils for back there again (lifetime warranty at O'Reilly) I have swapped 1,3 with 4,6 to verify that the problem moves to 4,6 upfront. But I want to find a cheap scan tool now so that I can verify that at home myself.

I can't help much, deck, but I have read a lot about the coil over plug on F150 trucks. Is the Mazda the coil over plug? Did you try a youtube search for those things? I learned a lot on youtube about my truck.

It has 6 coils, yes, coil over plug, i.e. distributor less ignition. Didn't find anything on YouTube about it.

If your car forums for your car has not helped yet, I don't know. I really depend on my car/truck forum for guys there to help out, and they are great about it. It might be a shot in the dark, but there is a car section on my very favorite forum, [www.mytractorforum.com]

Right, it's a forum about tractors mostly, but other sections too and like it says, it really is the friendliest forum (well, this one is great too!) there is. Check it out, scroll way down to the car section, sign up so you can ask your question, and maybe someone there can help. Or, I will ask your question for you if you want me to and let you know what I find out.

Be my guest! I was a member there last year for a lawn mower question but canceled it when I didn't see a continuing reason to stick around.

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deckeda
I want to set the vehicle aflame and call it a day.

Probably the best course of action with any American automotive technology over 100K miles.

I replaced all 6 on my MPV at about 75k as they all started going out one by one. That was ~55k miles ago, they are still going strong.

A quick google search
[www.google.com]

shows coils are a pretty common problem, but not usually recurring. Check your vacuum hoses, I had a leaky one (Texas Heat) and duck-taped it until I had time to replace it. I love my MPV, largest car I've ever enjoyed driving.

I just drove my Father's Ford 500 (same engine) 1200 miles and even though it handles GREAT (lower, wider), the MPV just felt livelier even though its about 90 lbs heavier. But if you know a "Ford Mechanic" have him take a look at it.
[autos.msn.com]

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San Antonio, TX (in the old city)

"All that is required for evil to prevail is for good men to do nothing."
-- Edmund Burke
"To announce that there must be no criticism of the President, or that we are to stand by the President, right or wrong, is not only unpatriotic and servile, but is morally treasonable to the American public." Theodore Roosevelt (1918)

Regarding the most common vacuum issue. My PCV hose went bad, as they all do in these. I made my own replacement after reading about it at mpvclub.com (great How To for the coils there as well ...) but that failed as well, and so eventually bought the latest design (!) from the dealer once the price went below $40.

Another crappy design that still doesn't fit well and made more complicated than necessary. They went through what, 3 PCV hose designs? And it's still weird. Noticed it also pulls a lot more oil into the intake than I recall PCV valves allow doing in other cars. But again, the PCV valve is another thing I've replaced recently.

I'm like you; the thing is great when it runs right, and handles much better than a van has any right to do. Makes you wonder "what would have been" had they brought the next-gen here in 2007.

When did cylinders start having individual coils? My wife's '07 Subie developed a misfiring problem, and time was tight, so I had the local shop deal with it. They diagnosed a bad coil, and ended up replacing the coil unit (containing all four, claiming that their experience was that when one went, the others were likely to follow) and the plugs, for about $500. Good grief! I've had plenty of cars with just a plain ol' coil and a distributor, and if the coil started to go you usually go plenty of warning, and you could just check the color of the spark.

/Mr Lynn

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"Hillbilly at Harvard"
Honky-tonk Country and Bluegrass
Founded in 1948 by Pappy Ben Minnich
Saturdays 9am - 1pm Eastern
WHRB-FM, Cambridge, MA
Streaming at [www.WHRB.org]
Be there!
New blog! [hillbillyatharvard.wordpress.com]

On the river in Saxonville.

Are your replacement coils genuine Ford replacements, or a third party? My 2002 Ford Escape with a 3.0L Duratec V6 has 167K miles on it and I've only replaced two coils - one at 100K and another at 160K.

Quote
deckeda
I'm like you; the thing is great when it runs right, and handles much better than a van has any right to do. Makes you wonder "what would have been" had they brought the next-gen here in 2007.

I really think they made the right choice in making the CX9. Better profit for Mazda who really needs it in America and it is still considered on the be best SUVs, four years on.
[www.motortrend.com]

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San Antonio, TX (in the old city)

"All that is required for evil to prevail is for good men to do nothing."
-- Edmund Burke
"To announce that there must be no criticism of the President, or that we are to stand by the President, right or wrong, is not only unpatriotic and servile, but is morally treasonable to the American public." Theodore Roosevelt (1918)

Quote
Forrest
Are your replacement coils genuine Ford replacements, or a third party? My 2002 Ford Escape with a 3.0L Duratec V6 has 167K miles on it and I've only replaced two coils - one at 100K and another at 160K.

The quality of the coils is a valid concern, sure. The initial replacements were Borg Warner ("BWD" ) and this second set was 2 from BWD and 1 Import Direct (what the auto parts store has in stock, where the lifetime warranty is).

I've read the design was improved early on, and that aftermarket coils are at least as good. Or maybe not! All I know is that there's no way to tell.

Coils from Ford or Mazda run somewhere around $130 ea. last time I looked. When I bought my 6 BWDs they were $75 each. The Import Direct models might be $5 less. And you can buy 6 of some kind via Amazon now for $120 or so ...



Edited 1 time(s). Last edit at 03/15/2012 08:38AM by deckeda.

Quote
mrlynn
When did cylinders start having individual coils?

/Mr Lynn

quite some time ago. my 1993 Volvo had them and I think that was the second or third year they offered that sort of ignition system.

as to the OP's problem, I would have to concur that it seems to be a QA problem OR it's an issue along the wiring harness to the coil that causes the coil to short out.