GMC Troubleshooting Questions? Ask a Mechanic for Answers
Hello and welcome!My name isCustomerand I can assist you with your question.
Are there any other codes in the computer other than the P0300?
Is the rough running at idle, under a load or both?
Ok, have you checked for vacuum leaks or fuel pressure?
Do you know what the engine vacuum is at when the engine is at idle?
No sir, this is not related to vacuum leaks. I am talking about the engine vacuum reading.
It is a reflection of how the engine is brearthing. It is a good way to measure and see if this is a base engine mechanical problem. For example, if you have a sticky valve, the vacuum gauge or needle will fuctuate at idle compared to an engine that is running good the vacuum needle will be nice and smooth at idle.
Anyway, the most common cause for this condition would be an issue with the timing chain or variable valve solenoid or actuator.
Here is a picture of the solenoid.
Here is a picture of the actuator.
You can also see the timing chain in the second picture. That could be an issue as well.
Yes Sir I do
I would check engine vacuum first. If it is low or unstable and there are no vacuum leaks, then the cheaper option would be to replace the camshaft actuator solenoid.
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Please let me know if you have any further questions.
It may or may not set a code if it goes bad.
Did you have any further questions?
I am sorry but I dont understand what your asking?
What computer? Your scanner or the cars computer?
What reading is it? Does it say engine vacuum?
Can you upload a picture for me?
YES it is possible but I would need to know what exactly your talking about to say for sure one way or the other