P0300 code on 08 Cobalt (#3 cyl misfire) - Chevrolet Forum - Chevy Enthusiasts Forums

P0300 code on 08 Cobalt (#3 cyl misfire)


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  #1  
Old  April 21st, 2011, 9:55 PM
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    Angleton, Texas
P0300 code on 08 Cobalt (#3 cyl misfire)

I have a question about my Cobalt. The car is a '08 XFE Cobalt with 97,500 miles on it. All of the mileage is highway miles to work and back. I also run nothing but 89 octane fuel and Mobil 1 Synthetic since first oil change. Last month, the engine light came on with the P0300 code (#3 cyl. misfire). The dealer tells me the coil is shorted, replaces it, and sends me on my way. This past Tuesday, the light comes on again with the same code and this time it goes in the "engine pwr reduced" mode and is missing real bad. Take it back to the dealer yesterday and they tell me it is an old code and there are no new codes. they pull a bulleton and tell me that the valve is sticking and the fuel system, injectors, and throttle body need to be cleaned. They recommend me using a fuel additive until I can bring it in to be cleaned. I get the car back and today the light come on again and goes into reduced pwr again. I drive straight to the dealer with the car barely running and they pull the codes again. It has the same P0300 code, a throttle body code, and now a all cyl misfire code. Now I feel better because I felt it was a electrical problem the whole time. Then they proceed to tell me that the misfire is due to the fuel system and sticking valves. What are the odds in ALL of the valves sticking at one time? This is starting to smell a little fishy. Does anyone have any other ideas of what the real problem may be? I doubt all the valves will stick at the same time. Thanks for listening, Steven

  #2  
Old  April 22nd, 2011, 4:22 PM
Would you happen to know if your dealership has involved our Technical Assistance team yet in regards to your issue? They would be able to assist the dealership with a diagnosis and repair for your vehicle. Also have you spoken with our Customer Assistance team to see if we can be of any help to you? Thank you for your time.

Jeff Morris, Chevrolet Customer Service

  #3  
Old  April 23rd, 2011, 1:54 AM
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Jeff,

I do not know if they contacted customer service or not. It just seems odd to me for all of the valves to stick at the same time. They replaced the throttle body yesterday and cleaned the injectors and valves. I'll see how it does next week when I go back to work. I drive 70 miles one way to work and it is all hwy at 65-70 mph. I have also used 89 octane fuel since day one and used Mobil 1 oil since the car has had 10,000 miles on it. The car has 97,500 miles on it and my warranty goes out at 100,140. I just want to make sure it is fixed before the warranty goes out. Thanks, Steven

  #4  
Old  April 25th, 2011, 9:00 AM
69rrvert, You would have to contact our Customer Assistance team and the dealership would contact the Technical Assistance team. I can steup a case for you with our Customer Assistance if you would like me to. Hopefully your dealership will be able to get this fully resolved for you.

Jeff Morris, Chevrolet Customer Service

  #5  
Old  April 26th, 2011, 7:47 AM
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Thanks for the help Jeff. The dealership replaced the throttle body and cleaned the injectors last Friday. I have not had any problems yet. If I do, I'll let you know. Thanks, Steven

  #6  
Old  April 26th, 2011, 8:42 PM
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Jeff,

I sent you a PM with the history. The light is on again in less than one tank of fuel. Thanks, Steven

  #7  
Old  April 28th, 2011, 9:42 PM
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Well, I picked up the rent car today. No they are going to replace the head. Supposedly it has bad valve seals. Wish me luck!!!!!!!!!!!!!!! Thanks, Steven


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