well i have dancing rpm in corolla 2009
in neutral position if blower is switched on rpm will drop from 900 to 500or even less ...
while moving 80 or 90km if i neutral the gear rpm will drop to 500 or less and then recover
maf sensor ok not dirty ..
throttle body serviced ...
battery changed to 65amp (problem increased with new battery )
only work around is that disconnect battery for 5 min and problem is resolved but issue returns upon restart ....