The check engine came on, and so pulled the code and a p0302 cylinder 2 misfire detected. So I change the plugs and it go's away, and comes back. So I change the coils and it went away and now it's back. I don't know what to check next. The miss can be felt at idle.
Cobalt has a misfire on cylinder 2
- Thread starter DreamerGT
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Why did you replace the spark plug and the coil? What pointed to an ignition misfire? Or are you just shot-gunning parts at the car in hopes something will fix it?
Could be partially clogged fuel injector. Same happened to me replaced everything then injector was faulty. Get it checked out!
If posting this is wrong please change:
Subject: Ecotec Misfire DTC's With No Concern Found- Inspect for Aftermarket Components
Models:
2004-07 Saturn Ion Redline
2005-07 Chevrolet Cobalt SS
With 2.0L Supercharged Engine (RPO LSJ)
2008-2010 Chevrolet Cobalt SS
2008-2010 Chevrolet HHR
2007-2009 Pontiac Solstice GXP
2007-2009 Saturn Sky Redline
With 2.0L Turbocharged Engine (RPO LNF)
Condition/Concern:
A technician may comment of MIL lamp on with DTC's of P0300, P0301, P0302 or P0304. They typically report they cannot determine a root cause. This concern (misfires) usually occurs with extended idling and may be reduced/eliminated by raising the RPM slightly or inducing an engine load (such as A/C).
Recommendation/Instructions:
Engineering has determined that aftermarket parts (such as a light weight aluminum flywheel or accessory belt drive pulleys) can contribute to this issue. Anytime any portion of the rotating assembly is changed to an aftermarket component, there is a potential for this concern. When diagnosing a misfire DTC and no concern can be found following eSI, the technician should inspect for aftermarket components installed. This concern (misfires) usually occurs with extended idling and may be reduced/eliminated by raising the RPM slightly or inducing an engine load (such as A/C).
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
Subject: Ecotec Misfire DTC's With No Concern Found- Inspect for Aftermarket Components
Models:
2004-07 Saturn Ion Redline
2005-07 Chevrolet Cobalt SS
With 2.0L Supercharged Engine (RPO LSJ)
2008-2010 Chevrolet Cobalt SS
2008-2010 Chevrolet HHR
2007-2009 Pontiac Solstice GXP
2007-2009 Saturn Sky Redline
With 2.0L Turbocharged Engine (RPO LNF)
Condition/Concern:
A technician may comment of MIL lamp on with DTC's of P0300, P0301, P0302 or P0304. They typically report they cannot determine a root cause. This concern (misfires) usually occurs with extended idling and may be reduced/eliminated by raising the RPM slightly or inducing an engine load (such as A/C).
Recommendation/Instructions:
Engineering has determined that aftermarket parts (such as a light weight aluminum flywheel or accessory belt drive pulleys) can contribute to this issue. Anytime any portion of the rotating assembly is changed to an aftermarket component, there is a potential for this concern. When diagnosing a misfire DTC and no concern can be found following eSI, the technician should inspect for aftermarket components installed. This concern (misfires) usually occurs with extended idling and may be reduced/eliminated by raising the RPM slightly or inducing an engine load (such as A/C).
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
If you didn't change the boots, change them too. That is likely where the spark is leaking out. Its common.
My Saturn ION was similar, and it had low compression at the misfiring cylinder. Hopefully this didn't happen to you.
JTK
$100 Site Donor 2025
Originally Posted By: DreamerGT
I pulled the coil boot off and looked at the spring it looked fine. So I put it back in and made sure it was making a connection to the coil. The is running fine now and the check engine light went off, so we'll see.
Hopefully that was it. Did you not touch the tube/boot part of the coil when you previously changed plugs and swapped coils?
Do you have aftermarket parts like that TSB describes?
I'm curious to the outcome here. You don't hear of too many Ecotec problems. A valve seating issue or head gasket problem causing low compression would be a nightmare I'd think. You'd have the timing chain to contend with before you pull the head.
Joel
I pulled the coil boot off and looked at the spring it looked fine. So I put it back in and made sure it was making a connection to the coil. The is running fine now and the check engine light went off, so we'll see.
Hopefully that was it. Did you not touch the tube/boot part of the coil when you previously changed plugs and swapped coils?
Do you have aftermarket parts like that TSB describes?
I'm curious to the outcome here. You don't hear of too many Ecotec problems. A valve seating issue or head gasket problem causing low compression would be a nightmare I'd think. You'd have the timing chain to contend with before you pull the head.
Joel
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Originally Posted By: DreamerGT
I also forgot to mention I wrapped the boot with electric tape, to see if the spark was leaking out like Scott Tucker said above. From what I can see there are no aftermarket part installed.
And the misfire went away after that?
I also forgot to mention I wrapped the boot with electric tape, to see if the spark was leaking out like Scott Tucker said above. From what I can see there are no aftermarket part installed.
And the misfire went away after that?
Probably just a bad boot. Very common. It's exactly like an open spark plug wire. The spark takes the path of least resistance - which in this case is to the spark plug tube.
Or maybe you had a bad boot and that electrical tape fixed it. Did you look at the label on that roll of electrical tape? It's not made for insulating against the high voltages you're subjecting it to. It shouldn't take long for a hole to burn through.
Wrapping electrical tape around the boot does not work. Try switching the boot to cyl 1 and see if the misfire moves. If if does its the boot. If it stays on 2 move the coil pack to cyl 1 and see if the misfire moves. If it does it's the coil pack.
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