2015 CX-5 Misfire

[Tribe&TrueRacin]

So many thoeries..... without more information....
First if you have NO DTC then your OBDII diagnostic connector is damage or the ECU is failing. I don't see anything that would indicate that. So no Engine check light move on.
A spark plug even new can start to have a performance issue. Only an oscilloscope can see this happening not the milage or brand. Trust me when I can show that a spark plug of any brand degrade after 5k miles and continues to degrade. So don't necessarily rule them out. Here again if they fire then it is not so likely to generate a DTC. Not all engine issues as you described will generate a DTC. Simple things like a dirty MAS or MAP of even the throttle body can cause problems and NEVER ECU generate a DTC.
I highly doubt it is a clogged fuel filter because if it were then your engine would have fuel supply issues causing a lean (AFR unbalanced beyond ECU tables adjusting limits) condition at a specific % of throttle that would generate a DTC. And your description on the fueling does not really point to the fuel filter. If I were looking the fuel pressure would be more my attention. But again if the fuel pump were going bad there would be a AFR adjustment in the ECU beyond limits which would and should generate a DTC.
Using any cleaners in the fuel tank would not be the best at this point and may actually exacerbate the problem. If the thought is faulty or fuel injectors function not operating within limits well most will always generate at least the basic P0300 DTC which is nothing more then anomalies out of programing condition of engine operation DTC. You don't place a band aid on a cut that may need stitches.

I recommend NOT guess and start tossing parts at the issue and look at the parts that are already there first.
If you cannot use a proper way of acerating the problem in a manor that will eliminate without adding problems that take your Mazda to a service shop.

Just saying.......

 

[50jeffrey]

Against my own better judgment, I pit another set of plugs in this morning and it didn't change a thing. Then drove the car to a reputable shop to be assessed, etc.

 

[50jeffrey]

Finally diagnosed with a bad no 4 ignition coil. I have a new coil and tried swapping g with no. 1 cinder last night, but did not follow through with trying the other cylinders. Shame on me. But an astonished that such a sever miss wouldn't trigger a P0304 code and set the check engine light.

 

[Tribe&TrueRacin]

Finally diagnosed with a bad no 4 ignition coil. I have a new coil and tried swapping with no. 1 cylinder last night, but did not follow through with trying the other cylinders. Shame on me. But an astonished that such a sever miss wouldn't trigger a P0304 code and set the check engine light.

Thats not unusual and complements to your service technician for using the proper problem solving steps to accurately find the issue. A coil can degrade but still energize and fire a spark plug. The results is a less then potent spark plug fire and the ECU would compensate the AFR , unfortunately across all the cylinders. Because of that the ECU would not detect a singe failing coil.
btw you changing the spark plugs didn't help because all spark plug will degrade less then what most people think. By replacing the spark plugs with new ones you help support the failing coil instead of resolving the issue. Yours is a prime example I mentioned earlier why guessing at parts and replacing them at times makes solving the original issue harder to find.

Nice to read your follow-ups on another MAZDA up and running with no current problems.

 

[HyFlyer]

This thread is an excellent example of good collective knowledge and suggestions leading to a good outcome.

Good job yawl and a fist-bump

And thanks @50jeffrey for the updates and followup post-repair report.

 

[sonicsc1]

just had same issue 2013 with 154000 miles on second set of plugs. wound up being weak coil pack and plugs bad i guess changed out all 4 and 1 coil pack. the dash would light up and car would go into limp mode

 

[AVC]

The criteria for setting or flashing the CEL for misfires is quite complex, with a priority not (typically) for engine performance but for (and required by OBD) whether out of bounds emissions and/or catalytic converter damage is imminent (i.e would seriously compromise emissions).

The PCM records misfires over 200 and 1000 revolution blocks and averages. If misfires exceed a lower threshold the CEL comes on steady for out of bounds emissions, if misfires exceed a higher threshold, it flashes, indicating pending catalyst damage.

The thresholds are different for every engine, but are, according to what I read, typically 1% ~ 5% misfires for a given measurement averaging block, under load. 25% ~ 40% misfires at idle.

While driving, if you have a scan tool that has access to OEM misfire counters, you can use them to diagnose misfires that are causing performance problems, which don't set CEL. A tech can often see high load misfires by using a coil paddle, while someone else does an in-Drive braking throttle blip.

 

[Tribe&TrueRacin]

I see someone have been doing some reading up.... most of what was posted is accurate but unfortunately not for all ECUs on platform manufactured from 2002 and newer. It is still easier by far to use an oscilloscope. The use of that is dying out because service shops won't invest in them, and it takes a few months to learn how to effectively use them to diagnosis most anything engine running related.

Oh, as a single example of why an oscilloscope is better diagnostic tool in most circumstance. A cracked insulator on a spark plug while normally running the engine (this means daily driving no load or over revving normal shifting point) will not generate nor create an anomalous condition to report the ECU as a misfire or held in memory as in service method described in post # 27 but will show graphed clearly on an oscilloscope.

Both the post #27 and mine are really useless to anyone except a certified and trained Automotive diagnostic technician anyway. Even dealerships have very few of them and many times will take their most experience service Tech and invest them into that platforms special Technician program to get a certification. Diagnostic skills and training are part of ASE Automotive Master Technicians testing certification program and they must re-test every few years to stay certified. I hold current L1 and L2.

 

[AVC]

It is accurate for many (I'd venture all OBD II vehicles I've owned since 2002) and more importantly accurate for these Mazda's. I've personally monitored all those parameters on the CX-5.

The scope isn't a substitute for a good scan tool, and vice versa. And you know better than to suggest otherwise.

Scope use is on the rise in shops, especially with younger techs, according to industry news (yes I do read); Snap-on, Autel, Pico, to name a few, all make excellent diagnostic scopes, probes, measurement sensors and provide training.

A curious DIY can put together a decent 2-channel scope and basic probes for well under $300. I like my Picoscope + homemade in-cylinder pressure transducer and multi-cylinder inductive paddles. I've learned a great deal about these Skyactiv the last 2 yrs.

I do concede there aren't many really curious/advanced DIY'ers. Most who post here (any forum) are just looking for the shortest path to a fix, and will run with guesses and wild guesses, aplenty. I get it; their car is broke and they're just hoping for a quick fix that doesn't require a dramatic, costly visit to a mechanic who has a 75% chance of being average at his job or worse.

 

[Tribe&TrueRacin]

It is accurate for many (I'd venture all OBD II vehicles I've owned since 2002) and more importantly accurate for these Mazda's. I've personally monitored all those parameters on the CX-5.

The scope isn't a substitute for a good scan tool, and vice versa. And you know better than to suggest otherwise.

you realize that that is well over 105+ for the most common and then there is the TCM if applicable in the ECU that could be
several dozen I am not even sure because it requires special programs to even access most of them?
I am also confused how you accessed the complete ECU mapping and PIDs without a program like MAZDA Versa Tune to read all the perimeters?? Maybe you just exaggerated a little?

I have several Scan tool include a Snap-on Solus and it is no even close to what an automotive scope can do. Besides both require either lots of self studying or being trained to use them both.
However I will agree using them both really gets the job done. I cant read test and use the test feature on a my scope but the Solus YUP! But then I cant read coil (high) performance on any scan tool but I can on my scope.

 

[ruthrj]

Pish posh. Everybody knows a Modis is superior to a Snap-On Solus.

 

[Tribe&TrueRacin]

Pish posh. Everybody knows a Modis is superior to a Snap-On Solus.

More off topic comments and responses...
*Umm you first need to have used both to compare... I have....
And pleeeeeez the word "superior" is not a very accurate description comparing the 2. One simply has more features but NOT superior. *But I guess that goes back to test driving both over a few weeks on several dozen or more different platforms!

My Snap-On rep. let me use one for 6 months. I found that there was no distinct advantage to warrant the cost to replace my Solis. While the very nice scope was handy it still did not have all the advantages of a full bench scope with available input/outputs to connect to any current Engine, chassis and transmission Dyno and its large scran makes it very easy to overlap perimeters and also print out any values watched. Perhaps if needed and wanted "bragging rights" I may consider that or the next level up when my solus becomes obsolete.

 

[ruthrj]

More off topic comments and responses...
*Umm you first need to have used both to compare... I have....
And pleeeeeez the word "superior" is not a very accurate description comparing the 2. One simply has more features but NOT superior. *But I guess that goes back to test driving both over a few weeks on several dozen or more different platforms!

My Snap-On rep. let me use one for 6 months. I found that there was no distinct advantage to warrant the cost to replace my Solis. While the very nice scope was handy it still did not have all the advantages of a full bench scope with available input/outputs to connect to any current Engine, chassis and transmission Dyno and its large scran makes it very easy to overlap perimeters and also print out any values watched. Perhaps if needed and wanted "bragging rights" I may consider that or the next level up when my solus becomes obsolete.

Lol, I’m just trolling you man. I googled what a solus was and went for it.

 

[AVC]

you realize that that is well over 105+ for the most common and then there is the TCM if applicable in the ECU that could be
several dozen I am not even sure because it requires special programs to even access most of them?
I am also confused how you accessed the complete ECU mapping and PIDs without a program like MAZDA Versa Tune to read all the perimeters?? Maybe you just exaggerated a little?

I have several Scan tool include a Snap-on Solus and it is no even close to what an automotive scope can do. Besides both require either lots of self studying or being trained to use them both.
However I will agree using them both really gets the job done. I cant read test and use the test feature on a my scope but the Solus YUP! But then I cant read coil (high) performance on any scan tool but I can on my scope.

 

[Kedis82ZE8]

Programs like OBD Link and Forscan can see almost everything... I remember when it was a shock that those programs even saw the AT temp sensor in CX-5.

 

[Tribe&TrueRacin]

you laugh dude?
Seriously please tell me how you fully accessed the MAZDA ECU to see what you claim?
I have a Versa Tune btw and even that has limits to what I can get into. While on the other hand have FULL ACCESS a program for another platform, I do EFI/CU Performance calibrating that has complete entry of all the tables in the ECU to adjust in a specific BMW platform. Also a Diablo Sport Tuner for a Chrysler and a Dimsport tunner for a MINI .
so really ..... you write very well indeed, I do not, but I do I practice what I post...

 

[AVC]