06 WRX strange noise
I also have been experiencing a strange noise with my new 06 wrx wagon. I have only had it for a month and it has 850 miles. I noticed the sound the day I drove it home from the dealer. I thought it sounded like it was pinging. It has continued to do so routinely under the same circumstances. The sound happens under light to moderate accelleration between the rpms of 2000 and 3000. It is more pronounced if the AC is on or if I am climbing a hill. It is also possible to feel a slight decrease in performance and stuttering, hesitance in the engine. As soon as the engine speed exceeds 3000 it quiets, smooths, and accellerates noticibly better.
I have just taken it to the dealer yesterday. A mechanic joined me for a test drive. He was easily able to hear it, he also said he could feel it from the passenger seat. He didn't think it was a ping. He said it did sound like it was coming from the engine bay. He described it as more of a "tick" to the service manager. I take it back to them tomorrow and leave it for a couple of days for them to drive it with the scan tool and to check in with Subaru. I'll let you know what I find out.
Incidentally, the fuel has been Sunoco 94 for the first two fill-ups, citgo 93 for the most recent. Fuel choice does not seem to have made a difference. I have been driving the car pretty gently during the break in for the most part. I still think the sound is ping.