2003 tiburon gt 2.7

when it starts RPM shoot up to 3000 and slowly go down to 1000 sometimes. very hard when driving to get back up to 3000 when it is in gear and will not exceed 3000.... took the idle air crontrol off and cleaned it cause it is making a buzzing noise and disconected the possitive to the battery and reconected it but now it will try and start but will not.... HELP plz. has anyone else had this problem? is it the iac valve? i am going today to get the obd2 scanner to tell me but i was really wanting to talk to someone who may have had this problem

 

The OBD-II scanner will only help if there is a code in the computer and the CEL is on. My guess is you messed something up by playing with the IAC but there could also be a problem with the throttle position sensor.