1995 Pontiac Firebird high idle

Every time I start my car it goes to 3000 rpm and keeps go n up no matter if,it's n,gear or neutral.. It will,go 55 mph with touch,n the gas.. I have changed the idel position sensor it did not help.every once in awhile it will start normally and idel right tell I shut it off.. That's one out of every 50 starts or more.. I have checked all the vacuum hoses..