What would cause my car to idle up high and then cut off?

if you have an older model car your carb my have a thermo coil choke and it will cause the engine to idle high... but won't kill it... unless you are in need of a tune up....

it could also be a problem with the way your float is adjusted and it will cause the carb to pour gas into the engine making it rev up then flood it out witch would kill it...

now on any fuel injected cars it could just be a simple miss fire.. if your car was made after 1995 it is possible that your check engne light will be on and tell you exactly where the problem is. most likely it's a miss fire