2001 Pontiac Montana high idle

hi i just replaced head gaskets on my van, had heads cut and checked before replacing. ok so i finished the job and the van ran fine until i test drove the van i drove around the corner and back by the time i got back around corner the van began to idle very high in drive like around 1300 rpm once in park van idle was 2900. i checked the tps sensor and was within specs, sprayed carb cleaner around intake to ckeck for vaccum leaks no change in idle. i tried un-hooking battery for 5 min but same thing after hooking back up. any suggestions would greatly be appreciated