Cylinder 5 Misfire

jb_camaro_2ss · 05-08-2023, 09:19 PM

I'm having a misfire on cylinder 5 (P0305 code) and I'm trying to figure out what to do next. It only happens after idling for a few seconds, illuminating the stabilitrak light, no matter if the engine is cold or warm. If I drive the car around the block, the stabilitrak light goes off and everything feels/sounds normal until it's time to sit at a stop and idle.

Here's what I've done and verified so far, clearing the code after each fix attempt, but the problem and code came back after each thing I did:
- Cylinder 5's spark plug looked great, replaced anyway
- Replaced the wire to cylinder 5
- Swapped cylinder 5's coil with cylinder 3 to see if the misfire would change cylinders... it did not
- Replaced the fuel injector and filled up with fresh gas

I'm outside of the warranty and I'm not sure what to do next to solve the problem. What do I need to check at this point? 2017 manual SS with 66k miles

95 imp · 05-08-2023, 09:28 PM

I'd get a VOM and test voltage of that coil at idle see if it's cutting out.

ctrlz · 05-09-2023, 09:17 AM

Do you have a scan tool that will let you look at fuel trims?

KingLT1 · 05-09-2023, 09:50 AM

compression test.

jb_camaro_2ss · 05-09-2023, 09:54 AM

Quote:

Originally Posted by 95 imp

I'd get a VOM and test voltage of that coil at idle see if it's cutting out.

I actually spent more time last night working on the car to try to figure this out. The coil is good and working as it should.

Quote:

Originally Posted by ctrlz

Do you have a scan tool that will let you look at fuel trims?

Yes, I will have some time check later in the week and I will report back.

Quote:

Originally Posted by KingLT1

compression test.

I haven't did a compression test yet. So I will add that to-do list.

I appreciate the responses from everyone!

Unclechopa · 07-09-2023, 04:15 AM

Take the valve cover off and start it check for any valve spring failure

Kamero6 · 07-09-2023, 12:20 PM

First, get a vacuum gauge and plug it in the intake where there is a vacuum port.
you should see a steady reading. If it jumps you have an issue there. At least you're ruling out valves and or Lifters this way and you don't have to tear enything apart.

Next will be a compression test. remove all spark plugs (8) and test all cylinders since you're already there. Compression test should be done without air filter and gas pedal at WOT which will open the throttle and cut the fuel at the same time.

After that, If all is Ok, I would start chasing electrical problems.
Usually cylinders with mechanical problems (valves, lifters, compression, etc..) start failing at idle.
It could also be cyl head gasket. Check for combustion gases in the coolant. (cheap and easy)

Good luck

05-08-2023, 09:19 PM	#1
jb_camaro_2ss Drives: 2017 2SS M6 Arctic Blue Join Date: Dec 2019 Location: Atlanta Posts: 64	Cylinder 5 Misfire I'm having a misfire on cylinder 5 (P0305 code) and I'm trying to figure out what to do next. It only happens after idling for a few seconds, illuminating the stabilitrak light, no matter if the engine is cold or warm. If I drive the car around the block, the stabilitrak light goes off and everything feels/sounds normal until it's time to sit at a stop and idle. Here's what I've done and verified so far, clearing the code after each fix attempt, but the problem and code came back after each thing I did: - Cylinder 5's spark plug looked great, replaced anyway - Replaced the wire to cylinder 5 - Swapped cylinder 5's coil with cylinder 3 to see if the misfire would change cylinders... it did not - Replaced the fuel injector and filled up with fresh gas I'm outside of the warranty and I'm not sure what to do next to solve the problem. What do I need to check at this point? 2017 manual SS with 66k miles __________________ Mod list: - AWE Touring Catback - BMR Springs - GM Dark Finish Taillights

05-08-2023, 09:28 PM	#2
95 imp Dumb Ass Deluxe Drives: A Tricked Out Mountain Bike Join Date: Jun 2019 Location: Arizona Posts: 1,959	I'd get a VOM and test voltage of that coil at idle see if it's cutting out. __________________

05-09-2023, 09:50 AM	#4
KingLT1 Drives: 2016 1SS NFG A8 Join Date: Aug 2017 Location: 46804 Posts: 6,843	compression test. __________________ 2016 NFG 1SS A8 Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA

05-09-2023, 09:17 AM	#3
ctrlz Drives: 2017 2SS, 50th pkg, M6, MRC, NPP Join Date: Jan 2016 Location: Ocean City, NJ Posts: 3,226	Do you have a scan tool that will let you look at fuel trims?

07-09-2023, 04:15 AM	#6
Unclechopa HSV re-engineered 2SS Drives: Chevrolet Camaro 2SS MY19 Join Date: Oct 2020 Location: Central Coast NSW Australia Posts: 14	Take the valve cover off and start it check for any valve spring failure

07-09-2023, 12:20 PM	#7
Kamero6 Drives: 6th Gen LT1 Join Date: Jun 2023 Location: Southeast Posts: 276	First, get a vacuum gauge and plug it in the intake where there is a vacuum port. you should see a steady reading. If it jumps you have an issue there. At least you're ruling out valves and or Lifters this way and you don't have to tear enything apart. Next will be a compression test. remove all spark plugs (8) and test all cylinders since you're already there. Compression test should be done without air filter and gas pedal at WOT which will open the throttle and cut the fuel at the same time. After that, If all is Ok, I would start chasing electrical problems. Usually cylinders with mechanical problems (valves, lifters, compression, etc..) start failing at idle. It could also be cyl head gasket. Check for combustion gases in the coolant. (cheap and easy) Good luck

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