Misfires without check engine on Softronic tuned 991.2
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2nd Gear
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Misfires without check engine on Softronic tuned 991.2
Hi All,
I recently bought a 2018 991.2 Carrera with a stage 1 @Softronic tune. Took it in to my local indy shop and was having the 40k maintenance done on it. Was not having any misfire issues before having the spark plugs replaced. They report after replacing the plugs, cylinder #1 keep showing a misfire after a road test. At that point, we replaced all 6 coils too and now having multiple misfires outside of cylinder #1 as well while viewing it live through their scan tool. Weird thing is the shop is saying it isn't throwing any codes or check engine light when misfiring. Has anyone had this issue with their tuned 991.2 after replacing the plugs/coils?
Unfortunately, the previous owner did not get the My Genius flash tool or files from the owner previous to them who bought the Softronic tune. I called Scott at Softronic but got voicemail today. Having the indy shop contact him as well to see if he has any idea.
Appreciate any insight.
I recently bought a 2018 991.2 Carrera with a stage 1 @Softronic tune. Took it in to my local indy shop and was having the 40k maintenance done on it. Was not having any misfire issues before having the spark plugs replaced. They report after replacing the plugs, cylinder #1 keep showing a misfire after a road test. At that point, we replaced all 6 coils too and now having multiple misfires outside of cylinder #1 as well while viewing it live through their scan tool. Weird thing is the shop is saying it isn't throwing any codes or check engine light when misfiring. Has anyone had this issue with their tuned 991.2 after replacing the plugs/coils?
Unfortunately, the previous owner did not get the My Genius flash tool or files from the owner previous to them who bought the Softronic tune. I called Scott at Softronic but got voicemail today. Having the indy shop contact him as well to see if he has any idea.
Appreciate any insight.
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Joined: Jan 2020
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From: CT
Hi All,
I recently bought a 2018 991.2 Carrera with a stage 1 @Softronic tune. Took it in to my local indy shop and was having the 40k maintenance done on it. Was not having any misfire issues before having the spark plugs replaced. They report after replacing the plugs, cylinder #1 keep showing a misfire after a road test. At that point, we replaced all 6 coils too and now having multiple misfires outside of cylinder #1 as well while viewing it live through their scan tool. Weird thing is the shop is saying it isn't throwing any codes or check engine light when misfiring. Has anyone had this issue with their tuned 991.2 after replacing the plugs/coils?
Unfortunately, the previous owner did not get the My Genius flash tool or files from the owner previous to them who bought the Softronic tune. I called Scott at Softronic but got voicemail today. Having the indy shop contact him as well to see if he has any idea.
Appreciate any insight.
I recently bought a 2018 991.2 Carrera with a stage 1 @Softronic tune. Took it in to my local indy shop and was having the 40k maintenance done on it. Was not having any misfire issues before having the spark plugs replaced. They report after replacing the plugs, cylinder #1 keep showing a misfire after a road test. At that point, we replaced all 6 coils too and now having multiple misfires outside of cylinder #1 as well while viewing it live through their scan tool. Weird thing is the shop is saying it isn't throwing any codes or check engine light when misfiring. Has anyone had this issue with their tuned 991.2 after replacing the plugs/coils?
Unfortunately, the previous owner did not get the My Genius flash tool or files from the owner previous to them who bought the Softronic tune. I called Scott at Softronic but got voicemail today. Having the indy shop contact him as well to see if he has any idea.
Appreciate any insight.
Make sure they used the correct stock plugs and they are gapped correctly as the wrong plugs will cause Misfires in all the Porsche cars and also bad coil packs etc. There is nothing in the tune either that would prevent the codes P0300 or P0301-P0306 from showing up either.
There have been bad supposively Original plugs coming from RockAuto....
Generally speaking go back to the last thing that started to cause a problem in any work..... The key is it wasn't having any problems before they replaced the plugs. I also didnt get any VM on this to call back.....
Semper Fi!
Scott
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Softronic - Porsche Performance Software Tuning
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Many 24HRS Daytona Winners programmed by Softronic! along with 1 lap of America and more.
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Porsche PCA racing binary check by Softronic for compliance.
Softronic - Porsche Performance Software Tuning
Faster than a speeding bullet.
Cayman | Boxster | 911 | Cayenne
Many 24HRS Daytona Winners programmed by Softronic! along with 1 lap of America and more.
Porsche Interseries programmed along with teamed owned Tudor ,World Challenge , PCA, IMSA and others in an exclusive with Softronic.
Porsche PCA racing binary check by Softronic for compliance.
Last edited by Softronic; Feb 19, 2026 at 06:49 PM. Reason: Added call
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Joined: Aug 2017
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From: we the north
Hello,
Make sure they used the correct stock plugs and they are gapped correctly as the wrong plugs will cause Misfires in all the Porsche cars and also bad coil packs etc. There is nothing in the tune either that would prevent the codes P0300 or P0301-P0306 from showing up either.
There have been bad supposively Original plugs coming from RockAuto....
Generally speaking go back to the last thing that started to cause a problem in any work..... The key is it wasn't having any problems before they replaced the plugs. I also didnt get any VM on this to call back.....
Semper Fi!
Scott
Make sure they used the correct stock plugs and they are gapped correctly as the wrong plugs will cause Misfires in all the Porsche cars and also bad coil packs etc. There is nothing in the tune either that would prevent the codes P0300 or P0301-P0306 from showing up either.
There have been bad supposively Original plugs coming from RockAuto....
Generally speaking go back to the last thing that started to cause a problem in any work..... The key is it wasn't having any problems before they replaced the plugs. I also didnt get any VM on this to call back.....
Semper Fi!
Scott
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Posts: 595
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From: Twin Cities, Minnesota
I'm gonna second the idea about checking the plug gap.
Mine had a slight misfire/hiccup at idle that didn't throw a code, and it turned out that one of the plugs was gapped improperly.
They come gapped correctly, but the theory is that, at the last plug swap, one of the plugs must have gotten dropped while in the box, so nobody checked the gap.
(This happened before my ownership, but my mechanic found the problem.)
Gap fixed, no issues since!
Mine had a slight misfire/hiccup at idle that didn't throw a code, and it turned out that one of the plugs was gapped improperly.
They come gapped correctly, but the theory is that, at the last plug swap, one of the plugs must have gotten dropped while in the box, so nobody checked the gap.
(This happened before my ownership, but my mechanic found the problem.)
Gap fixed, no issues since!
Burning Brakes
Joined: Jan 2019
Posts: 1,013
Likes: 538
From: Colorado
Agreed with the comments above. You didn't have any misfires with the Softronic tune installed then they change the spark plugs, then the coils, and now you're getting misfires. That's your clue.
I would ensure that they used OEM plugs and coils. When they got the misfire on the one cylinder, they should have just changed that plug, not throw a new (and costly) variable into the equation with replacing all of the coils. I know some people recommend changing coil packs at certain age/mileage but if you're not getting misfires and there are no visible cracks or damage to the coils, I think they can last a lot longer than people think.
I would ensure that they used OEM plugs and coils. When they got the misfire on the one cylinder, they should have just changed that plug, not throw a new (and costly) variable into the equation with replacing all of the coils. I know some people recommend changing coil packs at certain age/mileage but if you're not getting misfires and there are no visible cracks or damage to the coils, I think they can last a lot longer than people think.