I have a 2009 HHR LT with around 100k miles on it. I have been fairly diligent about regular oil changes and checking the coolant levels. The check engine light has never come on and there is no sign of overheating. Recently, when I push on the gas to accelerate, there seems to be a slight rattle or knocking from the engine compartment. It goes away when the gas pedal is released. It doesn't make the sound when it is idle or in parked. I'm thinking that it could be a symptom of spark knock?
Hello, and thank you for letting us help you with your automotive question. If the vehicle has not been tuned-up by this point then this is where you need to start. I would remove the spark plugs and inspect them. If they are worn this this can occur. If the plugs are fine then it may be due to a bad batch of fuel or dirty fuel injectors. Is the check engine light coming on?
No, the check engine light has never come on.
Okay. Thank you for the reply. Then I would start with checking the plugs. It would not hurt either to have the fuel injectors cleaned.