Engine revs when shifting.

Anyone with suggestions would be greatly appreciated. I have a 1998 Ranger 3.0L. Once it reaches normal operating temperature it has a tendency to rev up when I shift. It does not do it when cold and not always when warmed up, but on a pretty regular basis. Rather than the engine rpms dropping off when I take my foot off the gas to shift, it will run up through 3 or 4000 rpms. Thanks a bunch.

Check for vacuum leak. I had same problem on my 95 3.0 & found a broken hose going to the carbon canister. That's easiest & cheapest place to start. Good Luck!!