When I start my car after it's been sitting for awhile it seems to idle really high...like around 1,250 to 1,500 rpm for 5 minutes or so. Is this normal or is there a problem here?

 

Target idle RPM is determined by the ECM. Start up idle is always higher, even with a warm engine. The target idle RPM will decrease as the coolant sensor reports an increase in coolant temnperature, and as the O² sensor begins to report a useful signal.

That process may take a few minutes with a cold engine, and even a minute or longer with a warm engine. Make sure you are timing the process and not just guessing. Another thing to remember is that as the tachometer electronics age, the factory tachs tend to indicate a higher than actual RPM.