ArtOfRuin

iTrader: (1)

I took my S4 GXL on it's inaugural run to work yesterday. Shortly after I got onto the highway and up to 65mph, I heard a strange crackling noise coming from behind the dash (near the firewall?). At first I though it was some loose interior piece, but the sound did not go away when I fiddled with the dash. I don't think I warmed up the car enough because once it got to normal operaing temperature, the noise went away. I'll make sure to warm up the car to operating temperature before I hop on the highway from now on, but the noise concerns me.

The car is a S4 GXL, 98k miles. S4 N/A 13B, rebuilt 9 years ago at a Mazda stealership, 10K miles. Needs a new oil pan gasket; no other problems as far as I can tell. No mods aside from a K&N filter element. The car was at around 3000-3500rpms when the noise appeared. I backed off to about 50-55mph, 2500rpm, but the noise continued for about 1-3min. till the engine was up to normal operating temperature. No change in the car's performance during or after the incident. I plan on cleaning the grounds to see if that alleviates the problem. Any other thoughts?