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Document ID: 2355297
#PIP4717: Ecotec Misfire DTCs With No Concern Found - Inspect For Aftermarket Components - (Oct 1, 2009)

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)

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
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.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.


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I used to see the P0300 on my interceptor all of the time and brought it to the dealer 3 times. I never noticed a misfire and dont idle me car except when sitting at a red light. The tech told me it might be the guage and to unplug it to see if the code pops up. I told him the gauge was unplugged for 2 weeks before I plugged it in again and saw the code. this was when I was stock except for an injen intake.

I broke my interceptor so not I cant check to see if it still pops up.