I keep getting this code PO301 showing a misfire in cylinder #1 along with Service Stabilitrak and Service Traction Control messages. The engine is hesitating/stuttering terribly at idle and during road travel. Seems like it is even worse when the A/C is on. Didn't start happening until I filled up with Walmart/Murphy Oil gasoline.
Drivetrain still under warranty until August '12, but service tech says it won't cover plugs/wires/coil.
Can someone please guide me in the right direction?

It's a 2008 Impala LT with the 3900 V6 FlexFuel. 34,000 miles.

 

Inspect the connections of #1 spark plug wire making sure they are clean and tight. Try swapping the plug wire for #1 to a different cylinder and see if the misfire follows. If it does you know the wire is the problem. If not then swap the coil pack to a different location and see if the misfire follows. If it does then the coil pack is the problem. If not replace #1 spark plug. If the misfire is still present inspect/test the wiring for #1 injector. If you still have a misfire swap the fuel injector from #1 to a different location and see if the mifire follows. If it does try running some fuel injector cleaner through the system. If that doesn't help replace the injector.

 

<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <wontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" LatentStyleCount="156"> </w:LatentStyles> </xml><![endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} </style> <![endif]--> rsfurlong,

I'm sorry to hear that you are experiencing this issue with your Impala vehicle. This may be an injector issue. "03SSLE" offers good advice. However, if you are not comfortable doing it yourself, I encourage you to consult with a certified technician for additional assistance. They will be able to offer an official diagnosis after inspecting the vehicle.

Please keep us posted.

Louis
GM Customer Service

 

Thanks for the advice. I am going to inspect the plug first then try swapping wires, then the coil packs. I would take it to the dealer, but I just can't afford to pay $95 for a stinking diagnostic fee and then the additional jacked up parts/labor costs.
I will post my findings.

 

Well I removed the plug #1 wire and inspected. Found nothing out of ordinary. Put the plug wire back on and the car hasn't missed at all since. Must have been a bad/loose connection.