2013~2016: CX-5 misfiring After replacing spark plugs

[shindou26]

Hi All,

Running in some issues and hope you have any advice. I tried searching through the forum and applying what fixes were available, but I'm out of ideas now.

Routine maintenance replacing spark plugs with NGK Ruthenium. Decided to also replace ignition boots. After replacing everything, car ran rough and would misfire. I drove it around the block and a CEL came on. Instead of checking what the CEL was, I disconnected the battery and swapped everything back to the old spark plugs and ignition boots, but the same issues persisted with the misfiring and rough idle.

I swapped everything back to the new spark plugs and ignition boots and used an ODBII reader pulling the following codes:

P0302, misfire cylinder 2.
P061B, internal control module torque calculation performance.
P0102, mass or volume air flow circuit low input.
P0113, intake air pressure sensor 1 circuit high input.

Reset the reader twice and disconnected battery, but the same codes keep showing up. One thing to note is there is no CEL. These are codes that continue to appear even after everything.

During all of this, I noticed oil on two of the brand new spark plugs threads while the other two were still clean with no residual. I swapped out the valve cover gasket and replaced the MAF Sensor, but the same codes still appeared. I tried cleaning the IAT Sensor as well, but still the same codes with the same issues of misfiring and rough idle.

I also swapped around the ignition coils and spark plugs, but the same codes appear for cylinder 2.

I'm at a lost now for next steps. Everything was working fine with no issues before replacing the spark plugs. Issues only started after replacing the spark plugs.

 

[minnesotaart]

Really no idea what to tell you. However, if it was me, I'd swap the coil from cylinder #2 to a different cylinder and see if the codes shown move as well. If so, I'd replace all the ignition coils with the genuine Mazda article and also the plugs with genuine NKG Iridiums. I have sent photos of my new plugs directly to NKG before to verify that they are genuine since there are so many fakes out there. You can also test the resistance of the plugs to be sure they are genuine. Details on that are elsewhere on this forum. Good luck and let us know how it goes.

 

[felixd]

Hi All,

Running in some issues and hope you have any advice. I tried searching through the forum and applying what fixes were available, but I'm out of ideas now.

Routine maintenance replacing spark plugs with NGK Ruthenium. Decided to also replace ignition boots. After replacing everything, car ran rough and would misfire. I drove it around the block and a CEL came on. Instead of checking what the CEL was, I disconnected the battery and swapped everything back to the old spark plugs and ignition boots, but the same issues persisted with the misfiring and rough idle.

I swapped everything back to the new spark plugs and ignition boots and used an ODBII reader pulling the following codes:

P0302, misfire cylinder 2.
P061B, internal control module torque calculation performance.
P0102, mass or volume air flow circuit low input.
P0113, intake air pressure sensor 1 circuit high input.

Reset the reader twice and disconnected battery, but the same codes keep showing up. One thing to note is there is no CEL. These are codes that continue to appear even after everything.

During all of this, I noticed oil on two of the brand new spark plugs threads while the other two were still clean with no residual. I swapped out the valve cover gasket and replaced the MAF Sensor, but the same codes still appeared. I tried cleaning the IAT Sensor as well, but still the same codes with the same issues of misfiring and rough idle.

I also swapped around the ignition coils and spark plugs, but the same codes appear for cylinder 2.

I'm at a lost now for next steps. Everything was working fine with no issues before replacing the spark plugs. Issues only started after replacing the spark plugs.

Are your sure the plugs you ve bought are Genuine. If your car were running fine before replacing the plugs .. then it could be the New Plugs it self that are the problems because there are so many counterfeit plugs all over the interwebsz . Show us some photos of your new plugs vs old plugs.

 

[Boland01]

It's possible the ceramic insulator on the spark plug cracked during installation too. That could cause the misfire. Switch up the suspect plug with a good one or an old one and see if the misfire goes away. You can move it to another cylinder to and see if the misfire follows. If it does you have your answer.
If that doesn't work you might check your coils and trying moving one of them to a different cylinder.

 

[PTSanchez]

Was the #2 plug oiled-up?
Another vote for wonky plugs: please tell us that they were not purchased on eBay.

Regardless, suggest buzzing-out each new plug w/ an ohmmeter, then solving the oil fouling issue.

 

[Jmaz]

The OP didn't mention oil fouling on plugs, just had oil on plug threads and then changed valve cover gasket. I'd start by reinstalling the original plugs. I see the primary thing as getting it to run good again regardless of what codes are present. The lack of CEL indicates that these are "permanent/history" codes and represent problems that do not exist anymore, just that the old codes are still stored. The new plugs look like the source of the problem and not some stored codes.
If the old plugs get it running good again then I'd purchase verified genuine plugs. No ebay or Amazon. I'd even avoid Rockauto just to be sure. Just my 2 cents from what has been posted so far.

 

[Zoso]

If you still have the original boots, put those back in.

Did you buy oe boots from mazda or aftermarket? The ones I had got from rockauto were shorter than the oe boots and were causing issues like yours. Thought it was the new plugs at first, moved them around, changed them etc. Finally just put the original boots on and misfires were gone