After the G5 is warmed up, and I'm sitting at a stop light and it is quiet outside (usually at night) or I'm sitting in a drive thru, I hear this noise.

It sounds like a knock of some sorts, but it is only when the clutch pedal isn't pushed down and the trans is out of gear. When I hit the clutch it isn't there, and when I let the car idle in the parking lots or down my street in 1st or 2nd I can hear it too...and it is only there at idle, no where else in the rpm band.

Anyone got a clue as to what the heck it is?

 

Is it the "knock knock knock"?
There is a TSB out about it, it's the fuel pump, or something like that.

 

Evap canister i believe..

 

What would the fuel pump have to do with it only being at idle when the clutch is engaged? If the clutch is disengaged, then there is no knock.

 

its the Evap can cleaning itself out

 

I have never heard of this at all on any car, Even my 04 sunfire with the Getrag 5 and ecotec 2.2 never did this...

 

You cant compare your G5 to your past sunfire its not the same car. I have heard the noise you are talking about and thats what it is.

 

Dude, look at the cars much??? SAME EXACT MECHANICS, just different Chassis/Body/Suspension (hell even the suspension is almost identical except for a different spring rate)

My 04 Sunfire had the Ecotec 2.2L with the Getrag 5speed transmission. My 07 G5 has a 2.2 Ecotec with updated computer for the COP Ignition and a Getrag 5speed. Fuel delivery and all that is same.

If it is that, why does it only clean out when the clutch is engaged and either in Gear or N at idle? and Not disengaged?