That usually means that the key is getting worn down, but the lock could also be wearing out. If it also sometimes sticks in the ignition then probably the key, if only the driver's door, then the lock. Go to the dealer with your registration and VIN and order a new key cut ($20). If that doesn't fix the problem then it's time to replace the lock. If you have to replace the lock, you'll want to use a new key with it anyway. New keys feel soooo much better. The preferred lubricant for locks is powdered graphite (Mr. Zip)

__________________
-tp


1990 300SE "Corinne"- 145k daily driver - street modified differential - PARTING OUT OR SELLING SOON - PORTLAND OR. AREA - PM ME FOR DETAILS
1988 560SEL "Gunther"- 190K passes anything except a gas station
1997 S420 - 265k just bought it with a rebuilt trans. Lovely condition