Here is an addendum to my lazy Friday post. Some quick background: supply of gasoline falls (S1 to S2), prices rise (a to b), in the long run people adjust (b to c).
As I was reminded by a certain "dancing carpenter," once we move into the long run (more fuel efficient cars, shorter commutes, etc), there is now a new short run demand curve slicing through point c. In the graph on the right (click on the thumbnail for a bigger picture) it is labeled D3. Future changes in the supply of gasoline S2 will cause movement along D3. The long run demand, D2, is only a locus of short run equilibria. So, yes, the demand curve has shifted in response to an own-price change over the long run.
This sort of thing doesn't happen in a static, short-run analysis. Only in a dynamic analysis can the own-price change lead to a shift of the demand curve.
Comments are open, as always, but no complaints allowed if you don't like the basic D-S analysis, etc. This is a Saturday bonus post (i.e., a freebie)!