Mitsubishi Repair: Unknown Vibration, advanced auto parts, underdrive pulley

Question
I have a 96 Eclipse RS 2.0L with a manual tranny 186,000 miles.  There is a faint low frequency vibration that seems to be coming from the front driverside wheel area.  It is the most noticable between 35-50 mph while crusing in a straight line.  It seems to go away once I get above 50 mph. Neither braking, accelerating, or turning seem to effect it any.  I am the orignal owner of the car and I haven't had any work done to the car other then general maintinance.  Can you give me some idea of what it might be?

Thank you

Answer
Steve,
If the pitch of the sound does not change at all when either accelerating or braking, then your problem could be in your alternator.  The area you described is where the location of the alternator sits.  Though there is still a possibility you may have a worn wheel bearing, bad underdrive pulley, bad ball joint or worn tie-rod.  But first have the alternator checked.  Many auto parts stores like AutoZone, Advanced Auto Parts, and PepBoys can check your alternator for free.  If that does not reveal a problem, have your front suspension checked for worn out components.
Good luck!