Coil Pack Failure?

[gabkwong]

What are the symptoms of pending failure of the coil pack of the NB? Does it fails over a period of weeks/months or it comes out from the blue sky all a sudden? The problems/symptoms that I have with my 99 are:
1. CEL P1170, can’t fix this with new plug, new plug wires, new PCV vales, Seafoam and MAP sensor. All these fixes only make it idles better.
2. Idle drop. The idle can swing in a range of 200-250 RPMs. With all the fixes in No.1, it is idling better but still likes to drop 200 RPMs on extended idle , like 10 minutes.
3. Slight hesitation at highway speed. It is come and go. It is kind of very faint feeling that car is pulling something. When down shift and WOT it feels a little better. The car still making power and knocking or pining.
4. May be a slight drop in MPG (may 2 to 3 MPG), not very sure since I have been idling the car when working on it. One of result of P1170 CEL is running rich. The definition of P1170 is RPM > 15K, coolant temp > 190 and front O2 sensor > 0.45 for more than 43.25 seconds.

I am running out of idea how to fix this and any idea/suggestion are welcomed. I do have the Mazda diagnostic procedure for P1170. However, I do not have all the tools, vacuum gauge etc. to do all the tests. I will do those that I can this weekend. I am kind of thinking that the problem I have may be coil pack related!?

Thanks,
Gab

[POS Racing]

Get one of these it will solve all your problems.

[POS Racing]

Isn't the P1170 an O2 Sensor code? Ya sure you got good connections on your wiring?

[gabkwong]

Isn't the P1170 an O2 Sensor code? Ya sure you got good connections on your wiring?

Are you buying? The CB of me have invested on a OBII scanner and all sensors are reading signals. Therefor. wiring issues are r/o'ed. One thing I forgot to mention is that both the front and rear O2 sensor are brand new OEM units! $$$$

[creek]

Sure sounds like a vacuum leak to me.

[POS Racing]

P1170 shows up in my '99 service manual as a "Heated Oxygen Sensor (Front) (Inversion)" Whatever that means....

Have you asked at Miata.net they have a few more '99 owners that might know something.

My '99 had that hesitation issue once in a blue moon but only shortly after it had been started. I always figured it was just cold natured issue.

Have you checked compresion lately?

[gabkwong]

Sure sounds like a vacuum leak to me.

Paul, is there is good way to check that?

[gabkwong]

POS,

P1170 = RPM > 15K, coolant temp > 190 and front O2 sensor > 0.45 for more than 43.25 seconds. = runing rich

I posted at the Pointy Board and found some threads on this, but no one has ever say how they fix it.

The hesitation is at hwy speed and not the regular cold start hesitation which I am very used to. The odd thing is that the hesitation is around the same condition which triggers the CEL. That is why I think they are connected.

Yes, compression check in on list. If I can't get it fix by this weekend I will get a prof to check it for me.

[sammm]

When's the last time you put plug and wires on that car?

[motorollow]

When's the last time you put plug and wires on that car?

He just put new plugs and wires on a couple of weeks ago.

[shortshift]

I had a "heated O2 sensor" message for my Chevy truck lat year. It describes the sensor as being "heated" via the electrical connection. It sounds to me like the front O2 sensor is faulty, causing the computer to make the fuel/air mixture too rich. I realize the sensors were replaced, but sometimes new parts are faulty.

[black roadster]

Bad ?

[Awdieee]

I have a coil pack failure on my 97'. It all started with a P0300 misfire code and seeing that it was time to do my spark plugs and wires I swapped them out with NGKs. That help a little but after 8000 miles the symptoms worsen. I was stumbling very bad on the highway and managed to limp her back to my garage. Swapped out the coiled pack and she is running like a champ once again.

[joe.MIATA]

My 2 or 3 coil pack failures each occured suddenly on my '00. The car sputtered and barely drivable. I believe if the coil fails, it would be within 30-40K miles- but probably less. When the coil pack dies, it will also kill the cat (very soon after.) Remember, if its under 80K miles, the dealer will fix it under warranty- at least Hiley Mazda did- 2 or 3 times.