1) Look for external leaks - if you're smelling it, probably from the valve covers. Also, the oil pressure switch (passenger side, access from underneath) is known for dripping (would need to be replaced), though that wouldn't smell.
2) The valve stem seals typically wear out at a little over 100k miles. If so, you would typically see blue/black smoke out the exhaust at cold startup (may not notice it unless you back up right after starting and see a big cloud of smoke drift by you, would smell it too) *and* when giving it throttle after coasting at hiway speeds (like when you get behind a slower car and then punch it to pass - might not notice it unless you intentionally look for it out the back window, otherwise you won't notice it, but anyone following you couldn't miss it).
The oil pressure switch replacement is easy, valve cover gaskets are a little more work. Replacing the valve stem seals: Parts are inexpensive, but is a bit time consuming (24 valves, do one at a time). If you're going to do that, consider replacing the water pump (do *not* use an aftermarket one - get from dealer only, labor intensive), otherwise just keep driving it as is.
'98 LXi - Later Concorde gages (black w/ chrome rings)/'99 LX - LHS gages (white) - HIR bulbs