2012 MS3 Stuttering Under Load (Logs)

Swapped cyl 2 and 3 coils, misfire migrated to 3, so I swapped it with my old coil. Test drove it, throttle feels better, almost back to normal in terms of response, maybe placebo but I don’t think so. Pins in all the coils look straight. Problem does still persist.

Gonna clean out the filter and MAF to see but might be time for a new one. This filter is probably close to 6-7 years old if i would assume.

Will go under after to check everything PCV related next.
Any tips on closing the gap of the plugs without smashing it or one of those feeler gapping tools?
 
Currently under the car now, plugs to go in after.
Checking the PCV, all the hoses are still secure, the check valve on the OCC moves freely when shaking. Tested the flow, but I have no baseline as to how much vacuum I should be feeling or hearing in rpms. The vacuum was enough to suck my finger in a good amount and it was pretty audible from outside, engine rpm didnt drop much though. Dipstick smells relatively gas free, maybe a slight ting of gas.
 
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cbrandxn said:
Swapped cyl 2 and 3 coils, misfire migrated to 3, so I swapped it with my old coil. Test drove it, throttle feels better, almost back to normal in terms of response, maybe placebo but I don’t think so. Pins in all the coils look straight. Problem does still persist.

Gonna clean out the filter and MAF to see but might be time for a new one. This filter is probably close to 6-7 years old if i would assume.

Will go under after to check everything PCV related next.
Any tips on closing the gap of the plugs without smashing it or one of those feeler gapping tools?
Click to expand...
Misfire following a coil is generally pretty conclusive, and rules out wiring/control side problems to a coilpack as well. You mentioned you recently installed new coilpacks, was there a reason for that? Or just maintenance when it was running perfectly? You sure they aren't knockoff OEM coils? Does the p0303 persist with your old coil or just p0300?
 
Mazdasloww3 said:
Misfire following a coil is generally pretty conclusive, and rules out wiring/control side problems to a coilpack as well. You mentioned you recently installed new coilpacks, was there a reason for that? Or just maintenance when it was running perfectly? You sure they aren't knockoff OEM coils? Does the p0303 persist with your old coil or just p0300?
Click to expand...
No reason for replacing other than preventative, just maintenance. Yeah Im sure they're legit, had them ordered through my parts counter at my local mazda dealer.

Haven't had a chance to test to see if P0303 persists as the car is in pieces right now, haven't had the P0300 since the inital incident last week.
 
cbrandxn said:
No reason for replacing other than preventative, just maintenance. Yeah Im sure they're legit, had them ordered through my parts counter at my local mazda dealer.

Haven't had a chance to test to see if P0303 persists as the car is in pieces right now, haven't had the P0300 since the inital incident last week.
Click to expand...
Yeah they should be good then, but can't ever fully rule out parts issues. Have you checked the part number on the coils themselves to make sure a clueless parts guy didn't order base model coils, or even wrong parts were boxed (have had that happen, as frustrating as it is). Maybe try throwing all of your old coils in and see how it reacts?
 
After swapping the plugs yesterday, seems like most of the symptoms have gone away and there there is not much left to look at.

Will try swapping the newer previous coil back in later to see if the misfire problem persists after the plugs were installed, or if the codes just happen to be coincidental when changing the coils and it was the plugs all along.
 
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