Im having a problem with my engine reving to about 2500 hen dropping then reving back to 2500 over and over again. Its a 95 honda acoord f22b1.It only does it on start up but will do it until engine has warmed up. After warmed up the engine omeone told me it was the MAP sensor but that doesnt sound right. Any help would be much appreciated.

Vacuum leaks, sticky IAC (or whatever Honda calls it...ISC I think) or low coolant level are typical suspects...

MAP faults will usually make them run terrible or be hard to start, but not rolling idle...