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Slight misfire - but not throwing a CEL

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Slight misfire - but not throwing a CEL

 
Old 03-17-2019, 08:43 AM
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Unhappy Slight misfire - but not throwing a CEL

Hi Guys, I've read thru the misfire threads here which are extremely helpful. Mines a MY04 with just 60K miles on it. But only 6K miles in the past 7yrs so its been sitting in the garage a lot!

It's running good & idling appx 900rpm, but not as smooth as I think it should. At idle get a slight "skip" every 30 secs or so. When pulling hard under acceleration, it also occasionally misses 1 or 2 times, slight but noticeable to me. So far I am not getting any CEL. My OBD scan with Blue Driver shows no codes or pending codes. I did a TB cleaning and also cleaned and oiled my K&N filter first - no improvement.

Next I'm going to start with the likely suspects spark & fuel. The Denso plugs have been in 7 years but only have 6K miles, I'm going to pull those out first to take a peek and run a compression test. Will probably switch back to NGK's. Not sure how to test the coils.

I will also pull the injectors and have them tested & cleaned at RC Injector. Fuel pressure, filter, bad gas etc I will also look at. Any other likely suspects I should look at? Thanks a ton in advance.
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Old 03-17-2019, 10:04 AM
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Sounds like coil packs.
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Old 03-18-2019, 08:28 AM
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Originally Posted by Billman250 View Post
Sounds like coil packs.
Thanks Billman! Do you have a recommended procedure for testing the coil packs?
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Old 03-18-2019, 09:33 AM
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Just get 4 known good packs.

I have seen this first hand quite a few times (misfire heard/felt intermittently with no CEL)
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Old 03-18-2019, 09:52 AM
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Originally Posted by Billman250 View Post
Just get 4 known good packs.

I have seen this first hand quite a few times (misfire heard/felt intermittently with no CEL)
What would you say is the average lifespan of a set of coilpacks?

I recently discovered some oil on the coilpack of cylinder 4 (car threw a misfire cylinder 4 code). So obviously, I would have to replace the spark plug seals. Should I replace the coil packs too while I'm at it?

Year 2000, 130,000miles, car is in good mechanical shape otherwise.
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Old 03-18-2019, 09:55 AM
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100-125k'ish is the minimum time I've gotten on my Accord and S2000, separately, before one coil pack started to fail. But definitely a failure before 200k miles, at least in my experience.

And +1 for BIllman, I had a phantom coil pack on my AP1 which had similar symptoms as yours (and no CEL).
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Old 03-18-2019, 10:00 AM
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Very very hard to say.

My AP1 had a coil pack drop completely dead at 145k miles. It’s odd that it happened the ONE TIME I lent my GF the car at the time to drive 20 minutes to work. Replaced with 4 new AP2 packs.

I also have a customer with 280k on the original AP1 packs.
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Old 03-18-2019, 10:45 AM
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Originally Posted by Billman250 View Post
Very very hard to say.

My AP1 had a coil pack drop completely dead at 145k miles. It’s odd that it happened the ONE TIME I lent my GF the car at the time to drive 20 minutes to work. Replaced with 4 new AP2 packs.

I also have a customer with 280k on the original AP1 packs.
AP2 packs are compatible with AP1? Are the AP2 packs revised in anyway?

Thanks!
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Old 03-18-2019, 12:31 PM
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AP2 coil packs (04-05) are a more universal fit across other cars.

06-09 packs are not interchangeable.
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Old 03-18-2019, 02:22 PM
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Originally Posted by Billman250 View Post
AP2 coil packs (04-05) are a more universal fit across other cars.

06-09 packs are not interchangeable.
Do you have the part number(s) for the coil packs? AP1 or 2004-2005 AP2 will do, thanks!
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