4th gen making a light ping knock under acceleration

[T4RME]

I just got this 08 with 36k mi and I'm hyper sensitive to all noises it makes as I become accustomed to this vehicle. We take for granted that when you get a new car you have a smoothness, newness baseline to start from. Not so with a used car.

So I've noticed lately under medium to medium hard accel. from a stop around 2000 rpm a faint knock noise. Sounds like some old chevy struggling up a hill lol. Its not that bad yet. :guitar2:

 

[CJ3Flyr]

If it's a ping/knock related to gas I'd say top it with premium first. If some higher grade, different brand gas clears the problem then try 'regular' from a different station and don't use whatever gas it's pinging on. You may have received a bad batch of fuel.

If it still makes noise get the dealer to confirm the knock sensor is working to spec. It's supposed to advance the timing and lean the mixture to the point where it just begins to rattle a bit (inaudible to humans). If the sensor isn't quite right you may hear some knock but it still works well enough that the CEL light doesn't come on.

 

[T4RME]

Right on Chris thanks. I'll treat her to some of the good stuff next fill up.

Does the knock sensor work in real time and make adjustments on the fly? Just curious.

 

[CJ3Flyr]

Does the knock sensor work in real time and make adjustments on the fly? Just curious.

Yes, very much so... It listens and adjusts in real time, very, very quickly. If the root cause is bad fuel you'll know it within 5-10miles (or sooner). If the fuel doesn't fix it you have a bad knock sensor or some entirely different noise that just sounds similar.