I have a humming noise coming from my air filter, it seems to only happen after the car is driven for a while. I also only hear it AFTER the car is turned off. I've been trying to find the humming and found it last night. moved my spectre air intake a bit and it stopped humming, put it back down and humming came back. Any thoughts? It goes for about 30 seconds after the car is shut off, then fades out.