Even if it is just the air duct connecting the air filter housing to the throttle body broken (and not after the throttle body) it STILL effects the air metering device wheter it's a mass airflow or the flappy thing my car has,and it IS an input to the ECU if your car is fuel injected. So either way fix it
Barna
BTW the only time I had to put an engine in a Toyota (Pontiac Vibe) was when a lady went 53K miles on an oil change and of course never checked it since the car still ran so why bother(end sarcasm) Ok I admit I'm not a Toyota tech,I'm sure they do it more often.