Many normal repairs... as to be expected with 273,000!
I love my Park Avenue! My most recent issue is a vibration when I accelerate... that seems to go away when I let off the gas. I'm thinking it's time to rotate and balance the tires, and more importantly check the spark plugs and spark plug wires. Anyone agree?
I agree that the tire rotation, balancing, spark plug replacement, as well as a full service throttle body and injection cleaning is probably about due for your car. Also try a product called Heartland Engine Flush available at most lube shops.
Also check your transmission mounts. They will cause vibrations as well when they go bad.