Neon with a timed knock

Hey guys, I have a 2000 neon with a 2.0. recently it has developed a strange noise. It doesnt sound like a rod knock or a lifter so much as maybe a spark knock. It happens at exactly 8 second intervals while at idle. It doesnt get worse when you drive(put a load on the motor) but it does get faster(no longer 8 sec intervals). It seams to be at the front of the engine. A friend said it could be an alternater, idunno, it has me kinda stumped--any suggestions would be much appreciated--Thanks.