p2138 engine code

[crazylegs]

Just got my yaris 2 months ago, at first when the check engine light would come on my throttle response would just be shitty nothing more, after a few weeks i had a situation that freaked me out. While driving the throttle response went from normal to nothing and my car would just crawl forward at idle whether or not i was flooring the gas peddle. At first this only happened the one time and turning off the car and turning it back on fixed the issue, however in the last week it seems to be happening on a daily basis at random times, and it's driving me crazy!

engine code p2138
symptoms engine comes on and off at random, when engine light is on i have sluggish throttle response, and from time to time i have no throttle response which may go away in a few seconds or can last for as long as 15mins

solutions attempted
1.changed the peddle assembly with the APP sensor cleared the codes and within 5mins of driving the engine light came back on.
2. cleaned the mass air flow sensor, and the throttle body, cleared the codes and was able to drive for an hour without an issue. which made me feel that the issue was that the sensor or throttle body just needed to be cleaned.
3, took off the peddle assembly so i could return it and get my money back, cleared the codes and drove for 12mins then the engine light came back on.

now i'm just confused to hell what should be my next step in trouble shooting this issue. i have a new mass airflow sensor but i don't want to waste the $270 i paid for it putting it on the car just to find out it's not the issue. and if it's the throttle body sensor i feel like i just might as well look for a corolla TB and slap it on and call it a day.

anyone deal with this issue, love to get your feedback on how you tackled it.