knocking noise at idle

I just noticed today when i stop at a red light or when i am just sitting there idling i hear a knocking or almost a pinging noise coming from under the hood. When i rev the engine it goes away. The car runs fine and idles right where it should.

Try a couple tanks of supreme.

what year is the car? if its new it then you should just try really good fuel, if its not as new, then it might be something else.

Yea im starting to think its the gas i put in it because i usually only run premium but one day i only had a few dollars on me and i put in 89 octane gas and the next day i noticed the noise. My car is a 92' by the way.

Ya im guessing thats also the reason. Switch over to premium and see what happens.