the MAF sensor is in the Intake
use " throttle body " cleaner to clean it... refer to this thread:https://www.celicahobby.com/ubbthreads/thread.f_1862388016_0_collapsed_2__1.html
use the fuel injector cleaner as well, its a fuel additive that cleans from the inside of your engine, just put it in your gas tank the next time you fill up.
i recommend you check your Air Filter
too, and if its dirty replace it (or if you have a K&N just clean it)
pic of MAF circled in red