Misfire on one cylinder

RafalZajac · 12-18-2025, 03:30 AM

Hi everyone, I'm new to the forum. However, I have a problem with my 2019 Camaro 2.0 T.
I decided to replace the spark plug at 35,000 miles.
I used NGK replacements and unfortunately, they had a 1.2mm spark gap instead of 0.9mm, which made no difference at idle, but at high RPM, I experienced a misfire problem on the cylinders.
I went back to the old spark plugs and the problem disappeared, but only for a short time. After driving 40 miles, it reappeared and cylinder 4 completely misfired. I swapped the coil and spark plugs with cylinder 3, and unfortunately, the problem isn't with the coil or cylinder.
Does anyone have a wiring diagram for the ignition system? I suspect something on the low-voltage side has failed.

bishopts · 12-18-2025, 09:01 AM

Quote:

Originally Posted by RafalZajac

Hi everyone, I'm new to the forum. However, I have a problem with my 2019 Camaro 2.0 T.
I decided to replace the spark plug at 35,000 miles.
I used NGK replacements and unfortunately, they had a 1.2mm spark gap instead of 0.9mm, which made no difference at idle, but at high RPM, I experienced a misfire problem on the cylinders.
I went back to the old spark plugs and the problem disappeared, but only for a short time. After driving 40 miles, it reappeared and cylinder 4 completely misfired. I swapped the coil and spark plugs with cylinder 3, and unfortunately, the problem isn't with the coil or cylinder.
Does anyone have a wiring diagram for the ignition system? I suspect something on the low-voltage side has failed.

You don't want to suspect an injector?
If you have a problem with the wiring to the coils you're going to have a circuit fault code for that coil.

RafalZajac · 12-19-2025, 12:13 AM

258
They appeared. First P0300, then P0304, P0354, P050D. Unfortunately, I only have a Delphi diagnostic tool and can't clear them. I already bought VXDIAG for the Chevy, so I'll try today, but I need an electrical wiring diagram because it's hard to find the cables without one.

RafalZajac · 12-19-2025, 12:14 AM

The 6th generation Camaro was never sold in Europe so I have very limited access to documentation.

bishopts · 12-19-2025, 09:59 AM

Recheck your spark plugs. Use the new ones and gap them to the correct specifications. Visually check the porcelain to make sure you didn't crack them when they were installed. Check the connectors for the coils, i have a lot of them that the rubber insulation in the plug will bind when plugging in and it will keep the connector from plugging all the way in. I use dielectric grease as a lube on most any plug that i unplug.

I will try and get you a diagram later today or possibly tomorrow.

bishopts · 12-19-2025, 11:03 PM

ignition feed is from one fuse labeled
coil odd fuse
wire color is purple\blue and all coils have that wire

the Black\Blue wires they all share are low reference which is pcm ground
the pcm side of that is connector X2 cavity 44

yellow\blue is the coil control wire for cylinder 4
pcm X2 cavity 66

12-18-2025, 03:30 AM	#1
RafalZajac Drives: Camaro 2.0 T Join Date: Dec 2025 Location: Poland Posts: 3	Misfire on one cylinder Hi everyone, I'm new to the forum. However, I have a problem with my 2019 Camaro 2.0 T. I decided to replace the spark plug at 35,000 miles. I used NGK replacements and unfortunately, they had a 1.2mm spark gap instead of 0.9mm, which made no difference at idle, but at high RPM, I experienced a misfire problem on the cylinders. I went back to the old spark plugs and the problem disappeared, but only for a short time. After driving 40 miles, it reappeared and cylinder 4 completely misfired. I swapped the coil and spark plugs with cylinder 3, and unfortunately, the problem isn't with the coil or cylinder. Does anyone have a wiring diagram for the ignition system? I suspect something on the low-voltage side has failed.

12-19-2025, 12:13 AM	#3
RafalZajac Drives: Camaro 2.0 T Join Date: Dec 2025 Location: Poland Posts: 3	Ad 258 They appeared. First P0300, then P0304, P0354, P050D. Unfortunately, I only have a Delphi diagnostic tool and can't clear them. I already bought VXDIAG for the Chevy, so I'll try today, but I need an electrical wiring diagram because it's hard to find the cables without one.

12-19-2025, 11:03 PM	#6
bishopts Drives: 2017 2ss 6mt Join Date: Mar 2024 Location: dallas Posts: 944	ignition feed is from one fuse labeled coil odd fuse wire color is purple\blue and all coils have that wire the Black\Blue wires they all share are low reference which is pcm ground the pcm side of that is connector X2 cavity 44 yellow\blue is the coil control wire for cylinder 4 pcm X2 cavity 66 Attached Images

12-19-2025, 12:14 AM	#4
RafalZajac Drives: Camaro 2.0 T Join Date: Dec 2025 Location: Poland Posts: 3	The 6th generation Camaro was never sold in Europe so I have very limited access to documentation.

12-19-2025, 09:59 AM	#5
bishopts Drives: 2017 2ss 6mt Join Date: Mar 2024 Location: dallas Posts: 944	Recheck your spark plugs. Use the new ones and gap them to the correct specifications. Visually check the porcelain to make sure you didn't crack them when they were installed. Check the connectors for the coils, i have a lot of them that the rubber insulation in the plug will bind when plugging in and it will keep the connector from plugging all the way in. I use dielectric grease as a lube on most any plug that i unplug. I will try and get you a diagram later today or possibly tomorrow.

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